Thermoplastic polyester particles and methods of production and uses thereof

ABSTRACT

A method of producing thermoplastic particles may comprise: mixing a melt emulsion comprising (a) a continuous phase that comprises a carrier fluid having a polarity Hansen solubility parameter (dP) of about 7 MPa0.5 or less, (b) a dispersed phase that comprises a dispersing fluid having a dP of about 8 MPa0.5 or more, and (c) an inner phase that comprises a thermoplastic polyester at a temperature greater than a melting point or softening temperature of the thermoplastic polyester and at a shear rate sufficiently high to disperse the thermoplastic polyester in the dispersed phase; and cooling the melt emulsion to below the melting point or softening temperature of the thermoplastic polyester to form solidified particles comprising the thermoplastic polyester.

TECHNICAL FIELD

The present disclosure relates to thermoplastic polyester particles andmethods of making such particles. Such particles, especially the highlyspherical thermoplastic polyester particles, may be useful, among otherthings, as starting material for additive manufacturing.

BACKGROUND

Three-dimensional (3-D) printing, also known as additive manufacturing,is a rapidly growing technology area. Although 3-D printing hastraditionally been used for rapid prototyping activities, this techniqueis being increasingly employed for producing commercial and industrialobjects, which may have entirely different structural and mechanicaltolerances than do rapid prototypes.

3-D printing operates by depositing either (a) small droplets or streamsof a melted or solidifiable material or (b) powder particulates inprecise deposition locations for subsequent consolidation into a largerobject, which may have any number of complex shapes. Such deposition andconsolidation processes typically occur under the control of a computerto afford layer-by-layer buildup of the larger object. In a particularexample, consolidation of powder particulates may take place in a 3-Dprinting system using a laser to promote selective laser sintering(SLS). Incomplete interlayer fusion may result in structural weakpoints, which may be problematic for printing objects having exactingstructural and mechanical tolerances.

Powder particulates usable in 3-D printing include thermoplasticpolymers, including thermoplastic elastomers, metals and othersolidifiable substances. Although a wide array of thermoplastic polymersare known, there are relatively few having properties suitable for usein 3-D printing, particularly when using powder bed fusion (PBF).Additive manufacturing methods using powdered materials include PBF,selective laser sintering (SLS), selective heat sintering (SHM),selective laser melting (SLM), electron beam melting (EBM), binderjetting, and multi jet fusion (MJF). In the SLS printing method, theparticles are fused together by the energy from a high-powered laser.Typical thermoplastic polymers suitable for use in 3-D printing includethose having sharp melting points and recrystallization points about 20°C. to 50° C. below the melting point. This difference may allow for amore effective coalescence between adjacent polymer layers to takeplace, thereby promoting improved structural and mechanical integrity.

For good printing performance to be realized using powder particulates,particularly polymer powder particulates, the powder particulates needto maintain good flow properties in the solid state. Flow properties maybe evaluated, for example, by measuring the fraction of powderparticulates from a sample that are able to pass through a standardsieve of a specified size and/or measuring of the angle of repose. Highfractions of sievable powder particulates may be indicative of theparticulates existing as non-agglomerated, substantially individualparticulates, which may be characteristic of ready powder flow. Lowervalues of the angle of repose, in contrast, may be characteristic ofready powder flow. A relatively narrow particle size distribution andregularity of the particulate shape in a sample may also aid inpromoting good powder flow performance.

Commercial powder particulates are oftentimes obtained by cryogenicgrinding or precipitation processes, which may result in irregularparticulate shapes and wide particle size distributions. Irregularparticulate shapes may result in poor powder flow performance during 3-Dprinting processes. In addition, powder particulates having shapeirregularity, especially those obtained from current commercialprocesses, may afford poor packing efficiency following deposition andconsolidation, thereby resulting in extensive void formation in aprinted object due to the powder particulates not packing closelytogether during deposition. Wide particle size distributions may besimilarly problematic in this regard. Although poor powder flowperformance may be addressed to some degree through dry blending withfillers and flow aids, these techniques may have limited effectivenesswith softer polymer materials, such as elastomers, due to particulateaggregation.

SUMMARY OF THE INVENTION

The present disclosure relates to thermoplastic polyester particles andmethods of making such particles. Such particles, especially the highlyspherical thermoplastic polyester particles, may be useful, among otherthings, as starting material for additive manufacturing.

According to aspects illustrated herein, there is provided a methodcomprising: mixing a melt emulsion comprising (a) a continuous phasethat comprises a carrier fluid having a polarity Hansen solubilityparameter (d_(P)) of about 7 MPa^(0.5) or less, (b) a dispersed phasethat comprises a dispersing fluid having a d_(P) of about 8 MPa^(0.5) ormore, and (c) an inner phase that comprises a thermoplastic polyester ata temperature greater than a melting point or softening temperature ofthe thermoplastic polyester and at a shear rate sufficiently high todisperse the thermoplastic polyester in the dispersed phase; and coolingthe melt emulsion to below the melting point or softening temperature ofthe thermoplastic polyester to form solidified particles comprising thethermoplastic polyester.

According to aspects illustrated herein, there is provided a compositioncomprising: particles comprising a thermoplastic polyester, wherein theparticles have a sintering window that is within 5° C. of a sinteringwindow of the thermoplastic polyester.

BRIEF DESCRIPTION OF THE DRAWINGS

The following figures are included to illustrate certain aspects of theembodiments, and should not be viewed as exclusive embodiments. Thesubject matter disclosed is capable of considerable modifications,alterations, combinations, and equivalents in form and function, as willoccur to those skilled in the art and having the benefit of thisdisclosure.

FIG. 1 is a flow chart of a nonlimiting example of a multi-phase meltemulsion.

FIG. 2 is a flow chart of a nonlimiting example method 100 of thepresent disclosure.

FIG. 3A is an optical micrograph of the particles of Example 1.

FIG. 3B is an optical micrograph of the particles of Example 2.

FIG. 3C is an optical micrograph of the particles of Example 3.

FIG. 3D is an optical micrograph of the particles of Example 4.

FIG. 3E is an optical micrograph of the particles of Example 5.

FIG. 3F is an optical micrograph of the particles of Example 6.

FIG. 3G is an optical micrograph of the particles of Example 7.

FIG. 3H is an optical micrograph of the particles of Example 8.

FIG. 4A is a scanning electron micrograph of the particles of Example 3.

FIG. 4B is a scanning electron micrograph of the particles of Example 4.

FIG. 5A is a differential scanning calorimetry thermograph of particlesof Example 3.

FIG. 5B is a differential scanning calorimetry thermograph of particlesof Example 4.

FIG. 5C is a differential scanning calorimetry thermograph ofpolybutylene terephthalate (PBT) starting material.

FIG. 6A is a plot of the particle size distribution for Example 4,including the size statistics.

FIG. 6B is a plot of the particle size distribution for Example 8,including the size statistics.

FIG. 7 includes two pictures of the sintered layer from Example 9 at 45%laser power.

FIG. 8 includes two pictures of the sintered layer from Example 10 at45% laser power.

FIGS. 9A-B are scanning electron micrographs and FIGS. 9C-F arecross-section scanning electron micrographs of the particles of Example11.

FIGS. 10A-B includes two pictures of the sintered layer from Example 11at 45% laser power.

FIG. 11A-B are scanning electron micrographs and FIGS. 11C-F arecross-section scanning electron micrographs of the particles of Example12.

FIG. 12A-B are scanning electron micrographs and FIGS. 12C-F arecross-section scanning electron micrographs of the particles of Example13.

FIGS. 13A-B are pictures of the sintered layer from Example 13 at 45%laser power.

FIG. 14A-D includes scanning electron micrographs at variousmagnifications of the particles produced in Example 17.

FIG. 15 is a histogram of the particle size of the particles produced inExample 17.

FIG. 16A-E includes scanning electron micrographs at variousmagnifications of the particles produced in Example 18.

FIG. 17 is a histogram of the particle size of the particles produced inExample 18.

FIG. 18A-B are optical micrographs at various magnifications of theparticles produced in Example 19.

FIG. 19 is a histogram of the particle size of the particles produced inExample 19.

DETAILED DESCRIPTION

The present disclosure relates to polymer particles comprisingthermoplastic polyester and methods of making such particles. Suchparticles, especially the highly spherical polymer particles comprisingthermoplastic polyester, may be useful, among other things, as startingmaterial for additive manufacturing.

More specifically, the polymer particles described herein are producedby melt emulsification methods where said melt emulsion has three ormore phases. FIG. 1 illustrates a three-phase melt emulsion comprising(a) a continuous phase 102 that comprises a carrier fluid (e.g.,polydimethyl siloxane), (b) a dispersed phase 104 that comprises adispersing fluid, and (c) an inner phase 106 that comprises thethermoplastic polyester. The carrier fluid, dispersing fluid, andthermoplastic polyester are each immiscible with each other. While FIG.1 illustrates several inner phase droplets within in the dispersedphase, a dispersed phase droplet may have a single inner phase droplettherein.

Without being limited by theory, it is believed that hydrolysis and/orgrafting of polyesters in the melt emulsification process can cause areduction in the sintering window of the resultant particles. That is,temperature range under which sintering can be effectively performedreduces when the polyester is hydrolyzed and/or grafted. Therefore, thecomposition of the dispersed phase is preferably chosen to notcontribute to hydrolysis and/or grafting of the thermoplastic polyester.For example, hydroxyl terminal polyethylene glycol, which has been usedin other melt emulsification methods, can cleave polyester bonds viatransesterification mechanism. Further, the hydroxyl terminalpolyethylene glycol may be able to graft to the polyester or byproductsof polyester hydrolysis. Accordingly, alkyl-terminal polyethylene glycolare preferred in the dispersed phase because said polymers are inerttoward transesterification and cleavage of the polyester chains.Additionally, the methods described herein can be tailored to furthermitigate hydrolysis by one or more of: (a) performing the meltemulsification in an inert gas environment when not performed in anapparatus (e.g., an extruder) where an additional gas environment is notpresent and (b) using a carrier fluid that is less hygroscopic (if atall) minimize the hydrolysis due to the less water content.

In the methods described herein, a sufficient amount of shear is used todisperse the dispersing fluid in the carrier fluid and cause the polymermelt to form droplets in the dispersing fluid. As described furtherherein, to achieve an emulsion with three or more phases, thecomposition of said phases are chosen based on (a) solubility parametersand/or (b) viscosity at processing temperature.

Emulsion stabilizers (e.g., nanoparticles and/or surfactants, includingone or more members of each type in some cases) may be used to affectthe surface tension at the phase interface between the carrier fluid andthe polymer melt. Once the melt emulsification process is complete, thedispersion is cooled, which solidifies the polymer into polymerparticles. Without being limited by theory, during the meltemulsification process, the emulsion stabilizers primarily reside at theinterface between the polymer melt and the carrier fluid. As a result,when the mixture is cooled, the emulsion stabilizers remain at saidinterface. Advantageously, the emulsion stabilizers at a surface of theresultant particles may assist with the flow properties of the resultantparticles.

Definitions and Test Methods

As used herein, the term “immiscible” refers to a mixture of componentsthat, when combined, form two or more phases that have less than 5 wt %solubility in each other at ambient pressure and at room temperature orthe melting point of the component if it is solid at room temperature.For example, polyethylene oxide having 10,000 g/mol molecular weight isa solid at room temperature and has a melting point of 65° C. Therefore,said polyethylene oxide is immiscible with a material that is liquid atroom temperature if said material and said polyethylene oxide have lessthan 5 wt % solubility in each other at 65° C.

As used herein, the term “thermoplastic polymer” refers to a plasticpolymer material that softens/melts and hardens/solidifies reversibly onheating and cooling. Thermoplastic polymers encompass thermoplasticelastomers.

As used herein, the term “elastomer” refers to a copolymer comprising acrystalline “hard” section and an amorphous “soft” section. In the caseof a polyurethane, the crystalline section may include a portion of thepolyurethane comprising the urethane functionality and optional chainextender group, and the soft section may include the polyol, forinstance.

As used herein, the term “polyurethane” refers to a polymeric reactionproduct between a diisocyanate, a polyol, and an optional chainextender.

As used herein, the term “oxide” refers to both metal oxides andnon-metal oxides. For purposes of the present disclosure, silicon isconsidered to be a metal.

As used herein, the terms “associated,” “association,” and grammaticalvariations thereof between emulsion stabilizers and a surface refers tochemical bonding and/or physical adherence of the emulsion stabilizersto the surface. Without being limited by theory, it is believed that theassociations described herein between polymers and emulsion stabilizersare primarily physical adherences via hydrogen bonding and/or othermechanisms. However, chemical bonding may be occurring to some degree.

As used herein, the term “embed” relative to nanoparticles and a surfaceof a polymer particle refers to the nanoparticle being at leastpartially extending into the surface such that polymer is in contactwith the nanoparticle to a greater degree than would be if thenanoparticle were simply laid on the surface of the polymer particle.

Herein, D10, D50, D90, and diameter span are primarily used herein todescribe particle sizes. As used herein, the term “D10” refers to adiameter with 10% of the sample (on a volume basis, unless otherwisespecified) is comprised of particles having a diameter less than saiddiameter value. As used herein, the term “D50” refers to a diameter with50% of the sample (on a volume basis, unless otherwise specified) iscomprised of particles having a diameter less than said diameter value.As used herein, the term “D90” refers to a diameter with 90% of thesample (on a volume basis, unless otherwise specified) is comprised ofparticles having a diameter less than said diameter value.

As used herein, the terms “diameter span” and “span” and “span size”when referring to diameter provides an indication of the breadth of theparticle size distribution and is calculated as (D90-D10)/D50 (again,each D-value is based on volume, unless otherwise specified).

Particle size can be determined by light scattering techniques using aMalvern MASTERSIZER™ 3000 or analysis of optical digital micrographs.Unless otherwise specified, light scattering techniques are used foranalyzing particle size.

For light scattering techniques, the control samples were glass beadswith a diameter within the range of 15 μm to 150 μm under the tradenameQuality Audit Standards QAS4002™ obtained from Malvern Analytical Ltd.Samples were analyzed as dry powders, unless otherwise indicated. Theparticles analyzed were dispersed in air and analyzed using the AERO Sdry powder dispersion module with the MASTERSIZER™ 3000. The particlesizes were derived using instruments software from a plot of volumedensity as a function of size.

Particle size measurement and diameter span can also be determined byoptical digital microscopy. The optical images are obtained using aKeyence VHX-2000 digital microscope using version 2.3.5.1 software forparticle size analysis (system version 1.93).

As used herein, when referring to sieving, pore/screen sizes aredescribed per U.S.A. Standard Sieve (ASTM E11-17).

As used herein, the terms “circularity” and “sphericity” relative to theparticles refer to how close the particle is to a perfect sphere. Todetermine circularity, optical microscopy images are taken of theparticles. The perimeter (P) and area (A) of the particle in the planeof the microscopy image is calculated (e.g., using a SYSMEX FPIA 3000particle shape and particle size analyzer, available from MalvernInstruments). The circularity of the particle is C_(EA)/P, where C_(EA)is the circumference of a circle having the area equivalent to the area(A) of the actual particle.

As used herein, the term “sintering window” refers to the differencebetween the melting temperature (Tm) onset and the crystallizationtemperature (Tc) onset, or (Tm-Tc)onset. Tm, Tm(onset), Tc, andTc(onset) are determined by differential scanning calorimetry per ASTME794-06(2018) with a 10° C./min ramp rate and a 10° C./min cool rate.

As used herein, the term “shear” refers to stirring or a similar processthat induces mechanical agitation in a fluid.

As used herein, the term “aspect ratio” refers to length divided bywidth, wherein the length is greater than the width.

The melting point of a polymer, unless otherwise specified, isdetermined by ASTM E794-06(2018) with 10° C./min ramping and coolingrates.

The softening temperature or softening point of a polymer, unlessotherwise specified, is determined by ASTM D6090-17. The softeningtemperature can be measured by using a cup and ball apparatus availablefrom Mettler-Toledo using a 0.50 gram sample with a heating rate of 1°C./min.

Angle of repose is a measure of the flowability of a powder. Angle ofrepose measurements were determined using a Hosokawa Micron PowderCharacteristics Tester PT-R using ASTM D6393-14 “Standard Test Methodfor Bulk Solids” characterized by Carr Indices.

Hausner ratio (H_(r)) is a measure of the flowability of a powder and iscalculated by H_(r)=ρ_(tap)/ρ_(bulk), where ρ_(bulk), is the bulkdensity per ASTM D6393-14 and ρ_(tap) is the tapped density per ASTMD6393-14.

As used herein, viscosity of carrier fluids are the kinematic viscosityat 25° C., unless otherwise specified, measured per ASTM D445-19. Forcommercially procured carrier fluids (e.g., PDMS oil), the kinematicviscosity data cited herein was provided by the manufacturer, whethermeasured according to the foregoing ASTM or another standard measurementtechnique.

As used herein, Hansen solubility parameters are determined per HansenSolubility Parameters: A User's Handbook. Charles M. Hansen. CRC Press,Boca Raton, FL. 2007. 2^(nd) Ed. Further, the Hansen solubilityparameters for a mixture can be calculated by the volume-weightedaverage of the Hansen solubility parameters for each component in themixture. The total Hansen solubility parameter is the geometric mean ofthe three Hansen solubility components: d_(D) (from dispersioninteractions), d_(P) (from polar attraction), and dH (from hydrogenbonding).

Polymer Particles and Methods of Making

FIG. 2 is a flow chart of a nonlimiting example method 200 of thepresent disclosure. A polymer 202, carrier fluid 204, dispersing fluid206, and optionally an emulsion stabilizer (not illustrated) arecombined 208 to produce a mixture 210. The polymer 202 comprisesthermoplastic polyester and, optionally, one or more additionalthermoplastic polymers. The components 202, 204, and 206 can be added inany order and include mixing and/or heating during the process ofcombining 208 the components 202, 204, and 206.

Examples of thermoplastic polyesters include, but are not limited to,polybutylene terephthalate (PBT), polyethylene terephthalate (PET),polyethylene naphthalate (PEN), polytrimethylene terephthalate (PTT),polyhexamethylene terephthalate, and the like, and any combinationthereof.

The mixture 210 is then processed 212 by applying sufficiently highshear to the mixture 210 at a temperature greater than the melting pointor softening temperature of the polymer 202 to form a melt emulsion 214having three or more phases. More specifically, the melt emulsion maycomprise (a) a continuous phase that comprises the carrier fluid 204(e.g., polydimethylsiloxane), (b) a dispersed phase that comprises thedispersing fluid 206, and (c) an inner phase that comprises the polymer202. To achieve separate continuous and dispersed phases with the innerphase dispersed in the dispersed phase, the carrier fluid 204 preferablyhas a polarity Hansen solubility parameter (d_(P)) of about 7 MPa^(0.5)or less (or 0 MPa^(0.5) to 7 MPa^(0.5), or 0 MPa^(0.5) to 5 MPa^(0.5),or about 3 MPa^(0.5) to 7 MPa^(0.5)), and the dispersing fluid 206preferably has a d_(P) of about 8 MPa^(0.5) or more (or 8 MPa^(0.5) to30 MPa^(0.5), or 8 MPa^(0.5) to 15 MPa^(0.5), or 13 MPa^(0.5) to 20MPa^(0.5), or about 15 MPa^(0.5) to 30 MPa^(0.5)). Further, thedifference between the d_(P) of the dispersing fluid 206 and the d_(P)of the carrier fluid 204 is preferably 3 MPa^(0.5) or more (or 3MPa^(0.5) to 30 MPa^(0.5), or 3 MPa^(0.5) to 10 MPa^(0.5), or about 5MPa^(0.5) to 15 MPa^(0.5), or about 10 MPa^(0.5) to 20 MPa^(0.5), orabout 15 MPa^(0.5) to 30 MPa^(0.5)).

Because the temperature is above the melting point or softeningtemperature of the polymer 202, the polymer 202 becomes a polymer melt.By way of nonlimiting example, PBT has a softening temperature of about170° C. and a melting temperature of about 223° C. Accordingly, thetemperature of the mixing to form the melt emulsion 214 with PBT may beabout 180° C. to about 320° C. (or about 180° C. to about 250° C., orabout 200° C. to about 300° C., or about 225° C. to about 300° C.). Thetemperature may vary if additional thermoplastic polymers and/oradditional thermoplastic polyesters are used in addition to the PBT.More generally, the temperature of the mixing to form the melt emulsion214 may be about 150° C. to about 350° C. (or about 150° C. to about250° C., or about 200° C. to about 300° C., or about 250° C. to about350° C.). Again, temperatures outside these ranges may be applicabledepending on the polymers included in the process. The mixture 210 ispreferably substantially free of water (e.g., less than 1 wt % water) tomitigate hydrolysis of the thermoplastic polyester. Further, the mixturemay be heated in an inert gas environment (e.g., using nitrogen orargon) to mitigate the introduction of additional water into the mixture200.

Further, the shear rate should be sufficient enough to disperse thepolymer melt in the dispersing fluid 206 as droplets. Without beinglimited by theory, it is believed that, all other factors being thesame, increasing shear should decrease the size of the droplets of thepolymer melt in the carrier fluid 204. However, at some point there maybe diminishing returns on increasing shear and decreasing droplet size,or there may be disruptions to the droplet contents that decrease thequality of particles produced therefrom.

The melt emulsion 214 inside and/or outside the mixing vessel is thencooled 216 to solidify the polymer droplets into polymer particles (alsoreferred to as solidified polymer particles). The cooled mixture 218 canthen be treated 220 to isolate the polymer particles 222 from othercomponents 224 (e.g., the carrier fluid 204, the dispersing fluid 206,excess emulsion stabilizer when used, and the like) and wash, orotherwise purify, the polymer particles 222. The polymer particles 222comprise the polymer 202 and at least a portion of the emulsionstabilizer, when used, coating the outer surface of the polymerparticles 222. Emulsion stabilizers, or a portion thereof, may bedeposited as a uniform coating on the polymer particles 222. In someinstances, which may be dependent upon non-limiting factors such as thetemperature (including cooling rate), the type of polymer 202, and thetypes and sizes of emulsion stabilizers, the nanoparticles of emulsionstabilizers may become at least partially embedded within the outersurface of polymer particles 222 in the course of becoming associatedtherewith. Even without embedment taking place, at least thenanoparticles within emulsion stabilizers 206 may remain robustlyassociated with polymer particles 222 to facilitate their further use.In contrast, dry blending already formed polymer particulates (e.g.,formed by cryogenic grinding or precipitation processes) with a flow aidlike silica nanoparticles does not result in a robust, uniform coatingof the flow aid upon the polymer particulates.

Advantageously, carrier fluids, dispersing fluids, and washing solventsof the systems and methods described herein (e.g., method 200) can berecycled and reused. One skilled in the art will recognize any necessarycleaning of used carrier fluid, dispersing fluid, and solvent necessaryin the recycling process.

The polymer 202, the carrier fluid 204, and the dispersing fluid 206should be chosen such that at the various processing temperatures (e.g.,from room temperature to process temperature) the polymer 202, thecarrier fluid 204, and the dispersing fluid 206 are immiscible with eachother. An additional factor that may be considered is the differences in(e.g., a difference or a ratio of) viscosity at process temperaturebetween the molten polymer 202, the carrier fluid 204, and thedispersing fluid 206. The differences in viscosity may affect dropletbreakup and particle size distribution. Without being limited by theory,it is believed that when the viscosities of the molten polymer 202, thecarrier fluid 204, and the dispersing fluid 206 are too similar, thecircularity of the product as a whole may be reduced where the particlesare more ovular and more elongated structures are observed.

Examples of thermoplastic polymers that may be used in combination withthe thermoplastic polyester include, but are not limited to, polyamides,polyurethanes, polyethylenes, polypropylenes, polyacetals,polycarbonates, polystyrenes, polyvinyl chlorides,polytetrafluoroethenes, polyesters (e.g., polylactic acid), polyethers,polyether sulfones, polyetherether ketones, polyacrylates,polymethacrylates, polyimides, acrylonitrile butadiene styrene (ABS),polyphenylene sulfides, vinyl polymers, polyarylene ethers, polyarylenesulfides, polysulfones, polyether ketones, polyamide-imides,polyetherimides, polyetheresters, copolymers comprising a polyetherblock and a polyamide block (PEBA or polyether block amide), grafted orungrafted thermoplastic polyolefins, functionalized or nonfunctionalizedethylene/vinyl monomer polymer, functionalized or nonfunctionalizedethylene/alkyl (meth)acrylates, functionalized or nonfunctionalized(meth)acrylic acid polymers, functionalized or nonfunctionalizedethylene/vinyl monomer/alkyl (meth)acrylate terpolymers, ethylene/vinylmonomer/carbonyl terpolymers, ethylene/alkyl (meth)acrylate/carbonylterpolymers, methylmethacrylate-butadiene-styrene (MBS)-type core-shellpolymers, polystyrene-block-polybutadiene-block-poly(methylmethacrylate) (SBM) block terpolymers, chlorinated or chlorosulphonatedpolyethylenes, polyvinylidene fluoride (PVDF), phenolic resins,poly(ethylene/vinyl acetate)s, polybutadienes, polyisoprenes, styrenicblock copolymers, polyacrylonitriles, silicones, and the like, and anycombination thereof. Copolymers comprising one or more of the foregoingmay also be used in the methods and systems of the present disclosure.

The thermoplastic polymers in the compositions and methods of thepresent disclosure may be elastomeric or non-elastomeric. Some of theforegoing examples of thermoplastic polymers may be elastomeric ornon-elastomeric depending on the exact composition of the polymer. Forexample, polyethylene that is a copolymer of ethylene and propylene maybe elastomeric or not depending on the amount of propylene in thepolymer.

Thermoplastic elastomers generally fall within one of six classes:styrenic block copolymers, thermoplastic polyolefin elastomers,thermoplastic vulcanizates (also referred to as elastomeric alloys),thermoplastic polyurethanes, thermoplastic copolyesters, andthermoplastic polyamides (typically block copolymers comprisingpolyamide).

Examples of polyamides include, but are not limited to, polycaproamide(nylon 6, polyamide 6, or PA6), poly(hexamethylene succinamide) (nylon4,6, polyamide 4,6, or PA4,6), polyhexamethylene adipamide (nylon 6,6,polyamide 6,6, or PA6,6), polypentamethylene adipamide (nylon 5,6,polyamide 5,6, or PA5,6), polyhexamethylene sebacamide (nylon 6,10,polyamide 6,10, or PA6,10), polyundecaamide (nylon 11, polyamide 11, orPA11), polydodecaamide (nylon 12, polyamide 12, or PA12), andpolyhexamethylene terephthalamide (nylon 6T, polyamide 6T, or PA6T),nylon 10,10 (polyamide 10,10 or PA10,10), nylon 10,12 (polyamide 10,12or PA10,12), nylon 10,14 (polyamide 10,14 or PA10,14), nylon 10,18(polyamide 10,18 or PA10,18), nylon 6,18 (polyamide 6,18 or PA6,18),nylon 6,12 (polyamide 6,12 or PA6,12), nylon 6,14 (polyamide 6,14 orPA6,14), nylon 12,12 (polyamide 12,12 or PA12,12), and the like, and anycombination thereof. Copolyamides may also be used. Examples ofcopolyamides include, but are not limited to, PA 11/10,10, PA 6/11, PA6,6/6, PA 11/12, PA 10,10/10,12, PA 10,10/10,14, PA 11/10,36, PA11/6,36, PA 10,10/10,36, PA 6T/6,6, and the like, and any combinationthereof. A polyamide followed by a first number comma second number is apolyamide having the first number of backbone carbons between thenitrogens for the section having no pendent ═O and the second number ofbackbone carbons being between the two nitrogens for the section havingthe pendent ═O. By way of nonlimiting example, nylon 6,10 is[NH—(CH₂)₆—NH—CO—(CH₂)₈—CO]_(n). A polyamide followed by number(s)backslash number(s) are a copolymer of the polyamides indicated by thenumbers before and after the backslash.

Examples of polyurethanes include, but are not limited to, polyetherpolyurethanes, polyester polyurethanes, mixed polyether and polyesterpolyurethanes, and the like, and any combination thereof. Examples ofthermoplastic polyurethanes include, but are not limited to,poly[4,4′-methylenebis(phenylisocyanate)-alt-1,4-butanediol/di(propyleneglycol)/polycaprolactone], ELASTOLLAN™ 1190A (a polyether polyurethaneelastomer, available from BASF), ELASTOLLAN™ 1190A10 (a polyetherpolyurethane elastomer, available from BASF), and the like, and anycombination thereof.

Compatibilizers may optionally be used to improve the blendingefficiency and efficacy thermoplastic polyester with one or morethermoplastic polymers. Examples of polymer compatibilizers include, butnot limited to, PROPOLDER™ MPP2020 20 (polypropylene, available fromPolygroup Inc.), PROPOLDER™ MPP2040 40 (polypropylene, available fromPolygroup Inc.), NOVACOM™ HFS2100 (maleic anhydride functionalized highdensity polyethylene polymer, available from Polygroup Inc.), KEN-REACT™CAPS™ L™ 12/L (organometallic coupling agent, available from KenrichPetrochemicals), KEN-REACT™ CAPOW™ L™ 12/H (organometallic couplingagent, available from Kenrich Petrochemicals), KEN-REACT™ LICA™ 12(organometallic coupling agent, available from Kenrich Petrochemicals),KEN-REACT™ CAPS™ KPR™ 12/LV (organometallic coupling agent, availablefrom Kenrich Petrochemicals), KEN-REACT™ CAPOW™ KPR™ 12/H(organometallic coupling agent, available from Kenrich Petrochemicals),KEN-REACT™ titanates & zirconates (organometallic coupling agent,available from Kenrich Petrochemicals), VISTAMAXX™ (ethylene-propylenecopolymers, available from ExxonMobil), SANTOPRENE™ (thermoplasticvulcanizate of ethylene-propylene-diene rubber and polypropylene,available from ExxonMobil), VISTALON™ (ethylene-propylene-diene rubber,available from ExxonMobil), EXACT™ (plastomers, available fromExxonMobil) EXXELOR™ (polymer resin, available from ExxonMobil),FUSABOND™ M603 (random ethylene copolymer, available from Dow),FUSABOND™ E226 (anhydride modified polyethylene, available from Dow),BYNEL™ 41E710 (coextrudable adhesive resin, available from Dow), SURLYN™1650 (ionomer resin, available from Dow), FUSABOND™ P353 (a chemicallymodified polypropylene copolymer, available from Dow), ELVALOY™ PTW(ethylene terpolymer, available from Dow), ELVALOY™ 3427AC (a copolymerof ethylene and butyl acrylate, available from Dow), LOTADER™ AX8840(ethylene acrylate-based terpolymer, available from Arkema), LOTADER™3210 (ethylene acrylate-based terpolymer, available from Arkema),LOTADER™ 3410 (ethylene acrylate-based terpolymer, available fromArkema), LOTADER™ 3430 (ethylene acrylate-based terpolymer, availablefrom Arkema), LOTADER™ 4700 (ethylene acrylate-based terpolymer,available from Arkema), LOTADER™ AX8900 (ethylene acrylate-basedterpolymer, available from Arkema), LOTADER™ 4720 (ethyleneacrylate-based terpolymer, available from Arkema), BAXXODUR™ EC 301(amine for epoxy, available from BASF), BAXXODUR™ EC 311 (amine forepoxy, available from BASF), BAXXODUR™ EC 303 (amine for epoxy,available from BASF), BAXXODUR™ EC 280 (amine for epoxy, available fromBASF), BAXXODUR™ EC 201 (amine for epoxy, available from BASF),BAXXODUR™ EC 130 (amine for epoxy, available from BASF), BAXXODUR™ EC110 (amine for epoxy, available from BASF), styrenics, polypropylene,polyamides, polycarbonate, EASTMAN™ G-3003 (a maleic anhydride graftedpolypropylene, available from Eastman), RETAIN™ (polymer modifieravailable from Dow), AMPLIFY TY™ (maleic anhydride grafted polymer,available from Dow), INTUNE™ (olefin block copolymer, available fromDow), and the like and any combination thereof.

The thermoplastic polymers may have a melting point or softeningtemperature of about 50° C. to about 450° C. (or about 50° C. to about125° C., or about 100° C. to about 175° C., or about 150° C. to about280° C., or about 200° C. to about 350° C., or about 300° C. to about450° C.).

The thermoplastic polymers may have a glass transition temperature (ASTME1356-08(2014) with 10° C./min ramping and cooling rates) of about −50°C. to about 400° C. (or about −50° C. to about 0° C., or about −25° C.to about 50° C., or about 0° C. to about 150° C., or about 100° C. toabout 250° C., or about 150° C. to about 300° C., or about 200° C. toabout 400° C.).

The polymer 202 may optionally comprise an additive. Typically, theadditive would be present before addition of the polymer 202 to themixture 210. Therefore, in the polymer melt droplets and resultantpolymer particles, the additive is dispersed throughout the polymer.Accordingly, for clarity, this additive is referred to herein as an“internal additive.” The internal additive may be blended with thepolymer just prior to making the mixture 210 or well in advance.

When describing component amounts in the compositions described herein(e.g., the mixture 210 and polymer particles 222), a weight percentbased on the polymer 202 is not inclusive of the internal additive. Forexample, a composition comprising 1 wt % of emulsion stabilizer byweight of 100 g of a polymer 202 comprising 10 wt % internal additiveand 90 wt % polymer is a composition comprising 0.9 g of emulsionstabilizer, 90 g of polymer, and 10 g of internal additive.

The internal additive may be present in the polymer 202 at about 0.1 wt% to about 60 wt % (or about 0.1 wt % to about 5 wt %, or about 1 wt %to about 10 wt %, or about 5 wt % to about 20 wt %, or about 10 wt % toabout 30 wt %, or about 25 wt % to about 50 wt %, or about 40 wt % toabout 60 wt %) of the polymer 202. For example, the polymer 202 maycomprise about 70 wt % to about 85 wt % of a polymer and about 15 wt %to about 30 wt % of an internal additive like glass fiber or carbonfiber.

Examples of internal additives include, but are not limited to, fillers,strengtheners, pigments, pH regulators, and the like, and combinationsthereof. Examples of fillers include, but are not limited to, glassfibers, glass particles, mineral fibers, carbon fibers, oxide particles(e.g., titanium dioxide and zirconium dioxide), metal particles (e.g.,aluminum powder), and the like, and any combination thereof. Examples ofpigments include, but are not limited to, organic pigments, inorganicpigments, carbon black, and the like, and any combination thereof.

The polymer 202 may be present in the mixture 210 at about 5 wt % toabout 60 wt % (or about 5 wt % to about 25 wt %, or about 10 wt % toabout 30 wt %, or about 20 wt % to about 45 wt %, or about 25 wt % toabout 50 wt %, or about 40 wt % to about 60 wt %) of the polymer 202,carrier fluid 204, and the dispersing fluid 206 combined.

Suitable carrier fluids 204 have a viscosity at 25° C. of about 1,000cSt to about 150,000 cSt (or about 1,000 cSt to about 60,000 cSt, orabout 40,000 cSt to about 100,000 cSt, or about 75,000 cSt to about150,000 cSt).

Examples of carrier fluids 204 include, but are not limited to, siliconeoil, fluorinated silicone oils, perfluorinated silicone oils, paraffins,liquid petroleum jelly, vison oils, turtle oils, soya bean oils,perhydrosqualene, sweet almond oils, calophyllum oils, palm oils,parleam oils, grapeseed oils, sesame oils, maize oils, rapeseed oils,sunflower oils, cottonseed oils, apricot oils, castor oils, avocadooils, jojoba oils, olive oils, cereal germ oils, esters of lanolic acid,esters of oleic acid, esters of lauric acid, esters of stearic acid,fatty esters, higher fatty acids, fatty alcohols, polysiloxanes modifiedwith fatty acids, polysiloxanes modified with fatty alcohols,polysiloxanes modified with polyoxy alkylenes, and the like, and anycombination thereof. Examples of silicone oils include, but are notlimited to, polydimethylsiloxane, methylphenylpolysiloxane, an alkylmodified polydimethylsiloxane, an alkyl modifiedmethylphenylpolysiloxane, an amino modified polydimethylsiloxane, anamino modified methylphenylpolysiloxane, a fluorine modifiedpolydimethylsiloxane, a fluorine modified methylphenylpolysiloxane, apolyether modified polydimethylsiloxane, a polyether modifiedmethylphenylpolysiloxane, and the like, and any combination thereof.Suitable carrier fluids (individual or as mixtures) should be chosen soas not to decompose at the melt emulsion processing temperature.

Suitable dispersing fluids 206 have a viscosity at 25° C. of about 1,000cSt to about 150,000 cSt (or about 1,000 cSt to about 60,000 cSt, orabout 40,000 cSt to about 100,000 cSt, or about 75,000 cSt to about150,000 cSt).

Examples of dispersing fluids 206 include, but are not limited to,polyethylene glycols, alkyl-terminal polyethylene glycols (e.g., C1-C4terminal alkyl groups like tetraethylene glycol dimethyl ether (TDG)),esters of lanolic acid, esters of oleic acid, esters of lauric acid,esters of stearic acid, fatty esters, higher fatty acids, fattyalcohols, polysiloxanes modified with fatty acids, polysiloxanesmodified with fatty alcohols, polysiloxanes modified with polyoxyalkylenes, and the like, and any combination thereof.

It should be noted that some carrier fluid 204 and dispersing fluid 206compositions, in general terms, overlap because some compositions withinthese general categories can be used as carrier fluids 204 and others asdispersing fluids 206 (e.g., based on the degree of modification and/orthe type of modification (e.g., carbon chain length)). The d_(p) of theexact composition will determine if the composition is a carrier fluid204 or dispersing fluid 206.

Polyesters are susceptible to hydrolysis. Accordingly, water presentduring the melt emulsification production of the thermoplastic polyesterparticles may degrade the thermoplastic polyester, which may haveconsequences in the application of the thermoplastic polyesterparticles, for example, in additive manufacturing. Therefore, preferredcarrier fluids 204 include, but are not limited to, silicone oil,fluorinated silicone oils, perfluorinated silicone oils, paraffins,liquid petroleum jelly, vison oils, turtle oils, soya bean oils,perhydrosqualene, calophyllum oils, palm oils, parleam oils, maize oils,sunflower oils, apricot oils, avocado oils, jojoba oils, olive oils,cereal germ oils, esters of lanolic acid, esters of oleic acid, estersof lauric acid, esters of stearic acid, fatty esters, higher fattyacids, fatty alcohols, polysiloxanes modified with fatty acids,polysiloxanes modified with fatty alcohols, polysiloxanes modified withpolyoxy alkylenes, and the like, and any combination thereof. Further,preferred dispersing fluids 206 include, but are not limited to,alkyl-terminal polyethylene glycols. By way of nonlimiting example, acarrier fluid may comprise a silicone oil and an alkyl-terminalpolyethylene glycol.

The weight ratio of the carrier fluid and the dispersing fluid may beabout 1:3 to about 10:1 (or about 1:2 to about 5:1, or about 1:1 toabout 3:1). Without being limited by theory, it is believed that higherconcentrations of dispersing fluid may result in smaller diameterparticles. While other conditions (e.g., viscosity of each fluid,temperature, mixing speed, and the like) may play a role in producinglower diameter particles, a weight ratio of the carrier fluid and thedispersing fluid of about 1:3 to about 3:1 may be suitable for producingsmaller diameter particles.

The weight ratio of the dispersing fluid to the thermoplastic polyestermay be about 1:5 to about 10:1 (or about 1:3 to about 1:1, or about 1:2to about 3:1, or about 1:1 to about 5:1, or about 3:1 to about 10:1,).Without being limited by theory, it is believed that higherconcentrations of thermoplastic polyester may result in smaller diameterparticles. While other conditions (e.g., viscosity of each fluid,temperature, mixing speed, and the like) may play a role in producinglower diameter particles, a weight ratio of the dispersing fluid to thethermoplastic polyester of about 1:5 to about 2:1 may be suitable forproducing smaller diameter particles.

The carrier fluid 204 may be present in the mixture 210 at about 40 wt %to about 95 wt % (or about 75 wt % to about 95 wt %, or about 70 wt % toabout 90 wt %, or about 55 wt % to about 80 wt %, or about 50 wt % toabout 75 wt %, or about 40 wt % to about 60 wt %) of the polymer 202,the carrier fluid 204, and the dispersing fluid 206 combined. Thedispersing fluid 204 may be present in the mixture 210 at about 5 wt %to about 40 wt % (or about 5 wt % to about 15 wt %, or about 10 wt % toabout 25 wt %, or about 15 wt % to about 30 wt %, or about 20 wt % toabout 40 wt %) of the polymer 202, the carrier fluid 204, and thedispersing fluid 206 combined.

In some instances, the carrier fluid 204 may have a density of about 0.6g/cm³ to about 1.5 g/cm³, the dispersing fluid 206 may have a density ofabout 0.6 g/cm³ to about 1.5 g/cm³, and the polymer 202 has a density ofabout 0.7 g/cm³ to about 1.7 g/cm³, wherein the polymer has a densitysimilar, lower, or higher than the density of the carrier fluid and/ordispersing fluid.

The emulsion stabilizers may be used in the methods and compositions ofthe present disclosure and may comprise nanoparticles (e.g., oxidenanoparticles, carbon black, polymer nanoparticles, and combinationsthereof), surfactants, and the like, and any combination thereof.

Oxide nanoparticles may be metal oxide nanoparticles, non-metal oxidenanoparticles, or mixtures thereof. Examples of oxide nanoparticlesinclude, but are not limited to, silica, titania, zirconia, alumina,iron oxide, copper oxide, tin oxide, boron oxide, cerium oxide, thalliumoxide, tungsten oxide, and the like, and any combination thereof. Mixedmetal oxides and/or non-metal oxides, like aluminosilicates,borosilicates, and aluminoborosilicates, are also inclusive in the termmetal oxide. The oxide nanoparticles may by hydrophilic or hydrophobic,which may be native to the particle or a result of surface treatment ofthe particle. For example, a silica nanoparticle having a hydrophobicsurface treatment, like dimethyl silyl, trimethyl silyl, and the like,may be used in methods and compositions of the present disclosure.Additionally, silica with functional surface treatments likemethacrylate functionalities may be used in methods and compositions ofthe present disclosure. Unfunctionalized oxide nanoparticles may also besuitable for use as well.

Commercially available examples of silica nanoparticles include, but arenot limited to, AEROSIL™ particles available from Evonik (e.g., AEROSIL™R812S (about 7 nm average diameter silica nanoparticles having ahydrophobically modified surface and a BET surface area of 260±30 m²/g),AEROSIL™ RX50 (about 40 nm average diameter silica nanoparticles havinga hydrophobically modified surface and a BET surface area of 35±10m²/g), AEROSIL™ 380 (silica nanoparticles having a hydrophilicallymodified surface and a BET surface area of 380±30 m²/g), and the like,and any combination thereof.

Carbon black is another type of nanoparticle that may be present as anemulsion stabilizer in the compositions and methods disclosed herein.Various grades of carbon black will be familiar to one having ordinaryskill in the art, any of which may be used herein. Other nanoparticlescapable of absorbing infrared radiation may be used similarly.

Polymer nanoparticles are another type of nanoparticle that may bepresent as an emulsion stabilizer in the disclosure herein. Suitablepolymer nanoparticles may include one or more polymers that arethermosetting and/or crosslinked, such that they do not melt whenprocessed by melt emulsification according to the disclosure herein.High molecular weight thermoplastic polymers having high melting ordecomposition points may similarly comprise suitable polymernanoparticle emulsion stabilizers.

The nanoparticles may have an average diameter (D50 based on volume) ofabout 1 nm to about 500 nm (or about 10 nm to about 150 nm, or about 25nm to about 100 nm, or about 100 nm to about 250 nm, or about 250 nm toabout 500 nm).

The nanoparticles may have a BET surface area of about 10 m²/g to about500 m²/g (or about 10 m²/g to about 150 m²/g, or about 25 m²/g to about100 m²/g, or about 100 m²/g to about 250 m²/g, or about 250 m²/g toabout 500 m²/g).

Nanoparticles may be included in the mixture 210 at a concentration ofabout 0.01 wt % to about 10 wt % (or about 0.01 wt % to about 1 wt %, orabout 0.1 wt % to about 3 wt %, or about 1 wt % to about 5 wt %, orabout 5 wt % to about 10 wt %) based on the weight of the polymer 202.

Surfactants may be anionic, cationic, nonionic, or zwitterionic.Examples of surfactants include, but are not limited to, sodium dodecylsulfate, sorbitan oleates,poly[dimethylsiloxane-co-[3-(2-(2-hydroxyethoxy)ethoxy)propylmethylsiloxane],docusate sodium (sodium1,4-bis(2-ethylhexoxy)-1,4-dioxobutane-2-sulfonate), and the like, andany combination thereof. Commercially available examples of surfactantsinclude, but are not limited to, CALFAX™ DB-45 (sodium dodecyl diphenyloxide disulfonate, available from Pilot Chemicals), SPAN™ 80 (sorbitanmaleate non-ionic surfactant), MERPOL™ surfactants (available fromStepan Company), TERGITOL™ TMN-6 (a water-soluble, nonionic surfactant,available from DOW), TRITON™ X-100 (octyl phenol ethoxylate, availablefrom SigmaAldrich), IGEPAL™ CA-520 (polyoxyethylene (5) isooctylphenylether, available from SigmaAldrich), BRIJ™ S10 (polyethylene glycoloctadecyl ether, available from SigmaAldrich), and the like, and anycombination thereof.

Surfactants may be included in the mixture 210 at a concentration ofabout 0.01 wt % to about 10 wt % (or about 0.01 wt % to about 1 wt %, orabout 0.5 wt % to about 2 wt %, or about 1 wt % to about 3 wt %, orabout 2 wt % to about 5 wt %, or about 5 wt % to about 10 wt %) based onthe weight of the polymer 202. Alternatively, the mixture 210 maycomprise no (or be absent of) surfactant.

A weight ratio of nanoparticles to surfactant may be about 1:10 to about10:1 (or about 1:10 to about 1:1, or about 1:5 to about 5:1, or about1:1 to about 10:1).

As described above, the components 202, 204, and 206 and emulsionstabilizer (when used) can be added in any order and include mixingand/or heating during the process of combining 208 the components 202,204, and 206. For example, the dispersing fluid 206 may first bedispersed in the carrier fluid 204, optionally with heating saiddispersion, before adding the polymer 202 and emulsion stabilizer. Inanother nonlimiting example, the polymer 202 may be heated to produce apolymer melt to which the carrier fluid 204, dispersing fluid 106, andemulsion stabilizer are added together or in succession. In yet anothernonlimiting example, the dispersing fluid 206 and carrier fluid 204 canbe mixed at a temperature greater than the melting point or softeningtemperature of the polymer 202 and at a shear rate sufficient enough todisperse the polymer melt in the dispersing fluid 206. Then, theemulsion stabilizer can be added to form the mixture 210 and maintainedat suitable process conditions for a set period of time.

Combining 208 the components 202, 204, and 206 and emulsion stabilizer(when used) in any combination can occur in a mixing apparatus used forthe processing 212 and/or another suitable vessel. By way of nonlimitingexample, the polymer 202 may be heated to a temperature greater than themelting point or softening temperature of the polymer 202 in the mixingapparatus used for the processing 212, and the dispersing fluid 206 maybe dispersed in the carrier fluid 204 in another vessel. Then, saiddispersion may be added to the melt of the polymer 202 in the mixingapparatus used for the processing 212.

The mixing apparatuses used for the processing 212 to produce the meltemulsion 214 should be capable of maintaining the melt emulsion 214 at atemperature greater than the melting point or softening temperature ofthe polymer 202 and applying a shear rate sufficient to disperse thepolymer melt in the dispersing fluid 206 as droplets.

Examples of mixing apparatuses used for the processing 212 to producethe melt emulsion 214 include, but are not limited to, extruders (e.g.,continuous extruders, batch extruders, and the like), stirred reactors,blenders, reactors with inline homogenizer systems, and the like, andapparatuses derived therefrom.

Processing 212 and forming the melt emulsion 214 at suitable processconditions (e.g., temperature, shear rate, and the like) for a setperiod of time.

The temperature of processing 212 and forming the melt emulsion 214should be a temperature greater than the melting point or softeningtemperature of the polymer 202 and less than the decompositiontemperature of any components 202, 204, and 206 in the mixture 210. Forexample, the temperature of processing 212 and forming the melt emulsion214 may be about 1° C. to about 50° C. (or about 1° C. to about 25° C.,or about 5° C. to about 30° C., or about 20° C. to about 50° C.) greaterthan the melting point or softening temperature of the polymer 202,provided the temperature of processing 212 and forming the melt emulsion214 is less than the decomposition temperature of any components 202,204, and 206 in the mixture 210.

The shear rate of processing 212 and forming the melt emulsion 214should be sufficiently high to disperse the polymer melt in thedispersing fluid 206 as droplets. Said droplets should comprise dropletshaving a diameter of about 1000 μm or less (or about 1 μm to about 1000μm, or about 1 μm to about 50 μm, or about 10 μm to about 100 μm, orabout 10 μm to about 250 μm, or about 50 μm to about 500 μm, or about250 μm to about 750 μm, or about 500 μm to about 1000 μm).

The time for maintaining said temperature and shear rate for processing212 and forming the melt emulsion 214 may be 10 seconds to 18 hours orlonger (or 10 seconds to 30 minutes, or 5 minutes to 1 hour, or 15minutes to 2 hours, or 1 hour to 6 hours, or 3 hours to 18 hours).Without being limited by theory, it is believed that a steady state ofdroplet sizes will be reached, at which point processing 212 can bestopped. That time may depend on, among other things, the temperature,shear rate, polymer 202 composition, the carrier fluid 204 composition,the dispersing fluid 206 composition, and the emulsion stabilizercomposition.

The melt emulsion 214 may then be cooled 216. Cooling 216 can be slow(e.g., allowing the melt emulsion to cool under ambient conditions) tofast (e.g., quenching). For example, the rate of cooling may range fromabout 10° C./hour to about 100° C./second to almost instantaneous withquenching (for example in dry ice) (or about 10° C./hour to about 60°C./hour, or about 0.5° C./minute to about 20° C./minute, or about 1°C./minute to about 5° C./minute, or about 10° C./minute to about 60°C./minute, or about 0.5° C./second to about 10° C./second, or about 10°C./second to about 100° C./second).

During cooling, little to no shear may be applied to the melt emulsion214. In some instances, the shear applied during heating may be appliedduring cooling.

The cooled mixture 218 resulting from cooling 216 the melt emulsion 214comprises solidified polymer particles 222 (or simply polymer particles)and other components 224 (e.g., the carrier fluid 204, dispersing fluid206, excess emulsion stabilizer, and the like). The polymer particlesmay be dispersed in the carrier fluid or settled in the carrier fluid.

The cooled mixture 218 may then be treated 220 to the separate polymerparticles 222 (or simply polymer particles 222) from the othercomponents 224. Suitable treatments include, but are not limited to,washing, filtering, centrifuging, decanting, and the like, and anycombination thereof.

Solvents used for washing the polymer particles 222 should generally be(a) miscible with the carrier fluid 204 and/or dispersing fluid 206 and(b) nonreactive (e.g., non-swelling and non-dissolving) with the polymer202. The choice of solvent will depend on, among other things, thecomposition of the carrier fluid, the composition of the dispersingfluid, and the composition of the polymer 202.

Examples of solvents include, but are not limited to, hydrocarbonsolvents (e.g., pentane, hexane, heptane, octane, cyclohexane,cyclopentane, decane, dodecane, tridecane, and tetradecane), aromatichydrocarbon solvents (e.g., benzene, toluene, xylene, 2-methylnaphthalene, and cresol), ether solvents (e.g., diethyl ether,tetrahydrofuran, diisopropyl ether, and dioxane), ketone solvents (e.g.,acetone and methyl ethyl ketone), alcohol solvents (e.g., methanol,ethanol, isopropanol, and n-propanol), ester solvents (e.g., ethylacetate, methyl acetate, butyl acetate, butyl propionate, and butylbutyrate), halogenated solvents (e.g., chloroform, bromoform,1,2-dichloromethane, 1,2-dichloroethane, carbon tetrachloride,chlorobenzene, and hexafluoroisopropanol), water, and the like, and anycombination thereof.

Solvent may be removed from the polymer particles 222 by drying using anappropriate method such as air drying, heat drying, reduced pressuredrying, freeze drying, or a hybrid thereof. The heating may be performedpreferably at a temperature lower than the glass transition point of thepolymer (e.g., about 50° C. to about 150° C.).

The polymer particles 222 after separation from the other components 224may optionally be further classified to produce purified polymerparticles 228. For example, to narrow the particle size distribution (orreduce the diameter span), the polymer particles 222 can be passedthrough a sieve having a pore size of about 10 μm to about 250 μm (orabout 10 μm to about 100 μm, or about 50 μm to about 200 μm, or about150 μm to about 250 μm).

In another example of purification technique, the polymer particles 222may be washed with water to remove surfactant while maintainingsubstantially all of the nanoparticles associated with the surface ofthe polymer particles 222. In yet another example of purificationtechnique, the polymer particles 222 may be blended with additives toachieve a desired final product. For clarity, because such additives areblended with the particles 222 or other particles resultant from themethods described herein after the particles are solidified, suchadditives are referred to herein as “external additives.” Examples ofexternal additives include flow aids, other polymer particles, fillers,and the like, and any combination thereof.

In some instances, a surfactant used in making the polymer particles 222may be unwanted in downstream applications. Accordingly, yet anotherexample of purification technique may include at least substantialremoval of the surfactant from the polymer particles 222 (e.g., bywashing and/or pyrolysis).

The polymer particles 222 and/or purified polymer particles 228(referred to as particles 222/228) may be characterized by composition,physical structure, and the like.

As described above, the emulsion stabilizers are at the interfacebetween the polymer melt and the carrier fluid. As a result, when themixture is cooled, the emulsion stabilizers remain at, or in thevicinity of, said interface. Therefore, the structure of the particles222/228, in general, includes emulsion stabilizers (a) dispersed on anouter surface of the particles 222/228 and/or (b) embedded in an outerportion (e.g., outer 1 vol %) of the particles 222/228.

Further, where voids form inside the polymer melt droplets, emulsionstabilizers should generally be at (and/or embedded in) the interfacebetween the interior of the void and the polymer. The voids generally donot contain the polymer. Rather, the voids may contain, for example,carrier fluid, air, or be void. The particles 222/228 may comprisecarrier fluid at about 5 wt % or less (or about 0.001 wt % to about 5 wt%, or about 0.001 wt % to about 0.1 wt %, or about 0.01 wt % to about0.5 wt %, or about 0.1 wt % to about 2 wt %, or about 1 wt % to about 5wt %) of the particles 222/228.

The polymer 202 may be present in the particles 222/228 at about 90 wt %to about 99.5 wt % (or about 90 wt % to about 95 wt %, or about 92 wt %to about 97 wt %, or about 95 wt % to about 99.5 wt %) of the particles222/228.

The emulsion stabilizers, when used, may be present in the particles222/228 at about 10 wt % or less (or about 0.01 wt % to about 10 wt %,or about 0.01 wt % to about 1 wt %, or about 0.5 wt % to about 5 wt %,or about 3 wt % to about 7 wt %, or about 5 wt % to about 10 wt %) ofthe particles 222/228. When purified to at least substantially removesurfactant or another emulsion stabilizer, the emulsion stabilizers 206may be present in the particles 228 at less than 0.01 wt % (or 0 wt % toabout 0.01 wt %, or 0 wt % to 0.001 wt %).

Upon forming polymer particulates according to the disclosure herein, atleast a portion of the nanoparticles, such as silica nanoparticles, maybe disposed as a coating upon the outer surface of the polymerparticulates. At least a portion of the surfactant, if used, may beassociated with the outer surface as well. The coating may be disposedsubstantially uniformly upon the outer surface. As used herein withrespect to a coating, the term “substantially uniform” refers to an evencoating thickness in surface locations covered by the coatingcomposition (e.g., nanoparticles and/or surfactant), particularly theentirety of the outer surface. The emulsion stabilizers 206 may form acoating that covers at least 5% (or about 5% to about 100%, or about 5%to about 25%, or about 20% to about 50%, or about 40% to about 70%, orabout 50% to about 80%, or about 60% to about 90%, or about 70% to about100%) of the surface area of the particles 222/228. When purified to atleast substantially remove surfactant or another emulsion stabilizer,the emulsion stabilizers 206 may be present in the particles 228 at lessthan 25% (or 0% to about 25%, or about 0.1% to about 5%, or about 0.1%to about 1%, or about 1% to about 5%, or about 1% to about 10%, or about5% to about 15%, or about 10% to about 25%) of the surface area of theparticles 228. The coverage of the emulsion stabilizers 206 on an outersurface of the particles 222/228 may be determined using image analysisof the scanning electron microscope images (SEM micrographs). Theemulsion stabilizers 206 may form a coating that covers at least 5% (orabout 5% to about 100%, or about 5% to about 25%, or about 20% to about50%, or about 40% to about 70%, or about 50% to about 80%, or about 60%to about 90%, or about 70% to about 100%) of the surface area of theparticles 222/228. When purified to at least substantially removesurfactant or another emulsion stabilizer, the emulsion stabilizers 206may be present in the particles 228 at less than 25% (or 0% to about25%, or about 0.1% to about 5%, or about 0.1% to about 1%, or about 1%to about 5%, or about 1% to about 10%, or about 5% to about 15%, orabout 10% to about 25%) of the surface area of the particles 228. Thecoverage of the emulsion stabilizers 206 on an outer surface of theparticles 222/228 may be determined using image analysis of the SEMmicrographs.

The particles 222/228 may have a D10 of about 0.1 μm to about 125 μm (orabout 0.1 μm to about 5 μm, about 1 μm to about 10 μm, about 5 μm toabout 30 μm, or about 1 μm to about 25 μm, or about 25 μm to about 75μm, or about 50 μm to about 85 μm, or about 75 μm to about 125 μm), aD50 of about 0.5 μm to about 200 μm (or about 0.5 μm to about 10 μm, orabout 5 μm to about 50 μm, or about 30 μm to about 100 μm, or about 30μm to about 70 μm, or about 25 μm to about 50 μm, or about 50 μm toabout 100 μm, or about 75 μm to about 150 μm, or about 100 μm to about200 μm), and a D90 of about 3 μm to about 300 μm (or about 3 μm to about15 μm, or about 10 μm to about 50 μm, or about 25 μm to about 75 μm, orabout 70 μm to about 200 μm, or about 60 μm to about 150 μm, or about150 μm to about 300 μm), wherein D10<D50<D90. The particles 222/228 mayalso have a diameter span of about 0.4 to about 3 (or about 0.6 to about2, or about 0.4 to about 1.5, or about 1 to about 3). Withoutlimitation, diameter span values of 1.0 or greater are considered broad,and diameter spans values of 0.75 or less are considered narrow. Forexample, the particles 222/228 may have a D10 of about 5 μm to about 30μm, a D50 of about 30 μm to about 100 μm, and a D90 of about 70 μm toabout 120 μm, wherein D10<D50<D90. Said particles 222/228 may have adiameter span of about 0.5 to about 2.5.

The particles 222/228 may have a circularity of about 0.7 or greater (orabout 0.7 to about 0.95, or about 0.90 to about 1.0, or about 0.93 toabout 0.99, or about 0.95 to about 0.99, or about 0.97 to about 0.99, orabout 0.98 to 1.0).

The particles 222/228 may have an angle of repose of about 20° to about45° (or about 20° to about 30°, or about 25° to about 35°, or about 30°to about 40°, or about 35° to about 45°).

The particles 222/228 may have a Hausner ratio of about 1.0 to about 1.5(or about 1.0 to about 1.2, or about 1.1 to about 1.3, or about 1.2 toabout 1.35, or about 1.3 to about 1.5).

The particles 222/228 may have a bulk density of about 0.3 g/cm³ toabout 0.8 g/cm³ (or about 0.3 g/cm³ to about 0.6 g/cm³, or about 0.4g/cm³ to about 0.7 g/cm³, or about 0.5 g/cm³ to about 0.6 g/cm³, orabout 0.5 g/cm³ to about 0.8 g/cm³).

Depending on the temperature and shear rate of processing 212 and thecomposition and relative concentrations of the components 202, 204, and206, different shapes of the structures that compose the particles222/228 have been observed. Typically, the particles 222/228 comprisesubstantially spherical particles (having a circularity of about 0.97 orgreater). However, other structures including disc and elongatedstructures have been observed in the particles 222/228. Therefore, theparticles 222/228 may comprise one or more of: (a) substantiallyspherical particles having a circularity of 0.97 or greater, (b) discstructures having an aspect ratio of about 2 to about 10, and (c)elongated structures having an aspect ratio of 10 or greater. Each ofthe (a), (b), and (c) structures have emulsion stabilizers dispersed onan outer surface of the (a), (b), and (c) structures and/or embedded inan outer portion of the (a), (b), and (c) structures. At least some ofthe (a), (b), and (c) structures may be agglomerated. For example, the(c) elongated structures may be laying on the surface of the (a)substantially spherical particles.

The particles 222/228 may have a sintering window that is within 10° C.,preferably within 5° C., of the sintering window of the polymer 202(comprising thermoplastic polyester and optionally one or moreadditional thermoplastic polymers). Again, polyesters are susceptible tohydrolysis, especially at the temperatures of the melt emulsificationprocesses.

Applications of Polymer Particles Comprising Thermoplastic Polyester

The polymer particles described herein comprising thermoplasticpolyester and optionally one or more additional thermoplastic polymersmay be utilized in 3-D print processes, particularly those employingselective laser sintering to promote particulate consolidation. Thepolymer particles of the present disclosure may exhibit advantageousproperties over polymer particulates having irregular shapes or widerparticulate distributions, such as those available commercially. Innonlimiting examples, the polymer particles of the present disclosuremay undergo consolidation at lower laser powers and afford a decreasedextent of void formation in an object produced by 3-D printing.

3-D printing processes of the present disclosure may comprise:depositing polymer particles of the present disclosure upon a surface ina specified shape, and once deposited, heating at least a portion of thepolymer particles to promote consolidation thereof and form aconsolidated body (object), such that the consolidated body has a voidpercentage of about 1% or less after being consolidated. For example,heating and consolidation of the polymer particles may take place in a3-D printing apparatus employing a laser, such that heating andconsolidation take place by selective laser sintering.

Any of the polymer particles disclosed herein may be formulated in acomposition suitable for 3-D printing. Choice of the composition andtype of polymer particulate may be based upon various factors such as,but not limited to, the laser power used for selective laser sinter, thetype of object being produced, and the intended use conditions for theobject.

Examples of objects that may be 3-D printed using the polymer particlesof the present disclosure include, but are not limited to, containers(e.g., for food, beverages, cosmetics, personal care compositions,medicine, and the like), shoe soles, toys, furniture parts anddecorative home goods, plastic gears, screws, nuts, bolts, cable ties,automotive parts, medical items, prosthetics, orthopedic implants,aerospace/aircraft-related parts, production of artifacts that aidlearning in education, 3-D anatomy models to aid in surgeries, robotics,biomedical devices (orthotics), home appliances, dentistry, electronics,sporting goods, and the like.

Other applications for the particulates of the present disclosure mayinclude, but are not limited to, use as a filler in paints and powdercoatings, inkjet materials and electrophotographic toners, and the like.In some instances, the particulates may have other preferredcharacteristics like diameter and span to be useful in said otherapplications.

CLAUSES

Clause 1. A method comprising: mixing a melt emulsion comprising (a) acontinuous phase that comprises a carrier fluid having a polarity Hansensolubility parameter (d_(P)) of about 7 MPa^(0.5) or less, (b) adispersed phase that comprises a dispersing fluid having a d_(P) ofabout 8 MPa^(0.5) or more, and (c) an inner phase that comprises athermoplastic polyester at a temperature greater than a melting point orsoftening temperature of the thermoplastic polyester and at a shear ratesufficiently high to disperse the thermoplastic polyester in thedispersed phase; and cooling the melt emulsion to below the meltingpoint or softening temperature of the thermoplastic polyester to formsolidified particles comprising the thermoplastic polyester.

Clause 2. The method of Clause 1, wherein the temperature of the mixingis about 200° C. to about 320° C.

Clause 3. The method of Clause 1, wherein cooling is to a temperaturebelow 160° C.

Clause 4. The method of Clause 1, wherein the carrier fluid comprisesone selected from the group consisting of: silicone oil, fluorinatedsilicone oils, perfluorinated silicone oils, paraffins, liquid petroleumjelly, vison oils, turtle oils, soya bean oils, perhydrosqualene, sweetalmond oils, calophyllum oils, palm oils, parleam oils, grapeseed oils,sesame oils, maize oils, rapeseed oils, sunflower oils, cottonseed oils,apricot oils, castor oils, avocado oils, jojoba oils, olive oils, cerealgerm oils, esters of lanolic acid, esters of oleic acid, esters oflauric acid, esters of stearic acid, fatty esters, higher fatty acids,fatty alcohols, polysiloxanes modified with fatty acids, polysiloxanesmodified with fatty alcohols, polysiloxanes modified with polyoxyalkylenes, and any combination thereof.

Clause 5. The method of Clause 1, wherein the dispersing fluid comprisesone selected from the group consisting of: polyethylene glycols,alkyl-terminal polyethylene glycols (e.g., C1-C4 terminal alkyl groupslike tetraethylene glycol dimethyl ether (TDG)), esters of lanolic acid,esters of oleic acid, esters of lauric acid, esters of stearic acid,fatty esters, higher fatty acids, fatty alcohols, polysiloxanes modifiedwith fatty acids, polysiloxanes modified with fatty alcohols,polysiloxanes modified with polyoxy alkylenes, and any combinationthereof.

Clause 6. The method of Clause 1, wherein the carrier fluid comprises asilicone oil and the dispersing fluid comprises an alkyl-terminalpolyethylene glycol.

Clause 7. The method of Clause 1, wherein a weight ratio of the carrierfluid to the dispersing fluid of about 1:3 to about 100:1.

Clause 8. The method of Clause 1, wherein the thermoplastic polyester ispresent at 90 wt % to 99.5 wt % of the solidified particles.

Clause 9. The method of Clause 1, wherein the mixture further comprisesan emulsion stabilizer.

Clause 10. The method of Clause 9, wherein the emulsion stabilizer isassociated with a surface of the solidified particles.

Clause 11. The method of Clause 10, wherein at least a portion of theemulsion stabilizer is embedded in the surface of the solidifiedparticles.

Clause 12. The method of Clause 9, wherein the emulsion stabilizercomprises nanoparticles.

Clause 13. The method of Clause 9, wherein the solidified particlescomprise have a void comprising the emulsion stabilizer at avoid/thermoplastic polyester interface.

Clause 14. The method of Clause 1, wherein the solidified particles havea sintering window is within 5° C. of a sintering window of thethermoplastic polyester.

Clause 15. The method of Clause 1, wherein the solidified particles havea D10 of about 0.1 μm to about 125 μm, a D50 of about 0.5 μm to about200 μm, and a D90 of about 3 μm to about 300 μm, wherein D10<D50<D90.

Clause 16. The method of Clause 15, wherein the solidified particleshave a diameter span of about 0.4 to about 3.

Clause 17. The method of Clause 1, wherein the solidified particles havea D10 of about 0.5 μm to about 5 μm, a D50 of about 0.5 μm to about 10μm, and a D90 of about 3 μm to about 15 μm, wherein D10<D50<D90.

Clause 18. The method of Clause 1, wherein the solidified particles havea D10 of about 1 μm to about 50 μm, a D50 of about 25 μm to about 100μm, and a D90 of about 60 μm to about 300 μm, wherein D10<D50<D90.

Clause 19. The method of Clause 1, wherein the solidified particles havea D10 of about 5 μm to about 30 μm, a D50 of about 30 μm to about 100μm, a D90 of about 70 μm to about 120 μm, and a diameter span of about0.5 to about 2.5, wherein D10<D50<D90.

Clause 20. The method of Clause 1, wherein mixing occurs in an extruder.

Clause 21. The method of Clause 1, wherein mixing occurs in a stirredreactor under an inert gas environment.

Clause 22. The method of Clause 1, wherein the solidified particles havea circularity of about 0.90 to about 1.0.

Clause 23. The composition of Clause 1, wherein the solidified particleshave a Hausner ratio of about 1.0 to about 1.5.

Clause 24. The method of Clause 1, wherein the thermoplastic polyestercomprises one selected from the group consisting of: polybutyleneterephthalate (PBT), polyethylene terephthalate (PET), polyethylenenaphthalate (PEN), polytrimethylene terephthalate (PTT),polyhexamethylene terephthalate, and any combination thereof.

Clause 25. The method of Clause 1, wherein the mixture further comprisesa thermoplastic polymer selected from the group consisting of:polyamides, polyurethanes, polyethylenes, polypropylenes, polyacetals,polycarbonates, polystyrenes, polyvinyl chlorides,polytetrafluoroethenes, polyesters (e.g., polylactic acid), polyethers,polyether sulfones, polyetherether ketones, polyacrylates,polymethacrylates, polyimides, acrylonitrile butadiene styrene (ABS),polyphenylene sulfides, vinyl polymers, polyarylene ethers, polyarylenesulfides, polysulfones, polyether ketones, polyamide-imides,polyetherimides, polyetheresters, copolymers comprising a polyetherblock and a polyamide block (PEBA or polyether block amide), grafted orungrafted thermoplastic polyolefins, functionalized or nonfunctionalizedethylene/vinyl monomer polymer, functionalized or nonfunctionalizedethylene/alkyl (meth)acrylates, functionalized or nonfunctionalized(meth)acrylic acid polymers, functionalized or nonfunctionalizedethylene/vinyl monomer/alkyl (meth)acrylate terpolymers, ethylene/vinylmonomer/carbonyl terpolymers, ethylene/alkyl (meth)acrylate/carbonylterpolymers, methylmethacrylate-butadiene-styrene (MBS)-type core-shellpolymers, polystyrene-block-polybutadiene-block-poly(methylmethacrylate) (SBM) block terpolymers, chlorinated or chlorosulphonatedpolyethylenes, polyvinylidene fluoride (PVDF), phenolic resins,poly(ethylene/vinyl acetate)s, polybutadienes, polyisoprenes, styrenicblock copolymers, polyacrylonitriles, silicones, and any combinationthereof.

Clause 26: The method of Clause 1, wherein a weight ratio of the carrierfluid and the dispersing fluid is about 1:3 to about 10:1 (or about 1:2to about 5:1, or about 1:1 to about 3:1).

Clause 27: The method of Clause 1, wherein a weight ratio of the carrierfluid and the dispersing fluid is about 1:3 to about 3:1.

Clause 28: The method of Clause 1, wherein a weight ratio of thedispersing fluid to the thermoplastic polyester is about 1:5 to about10:1 (or about 1:3 to about 1:1, or about 1:2 to about 3:1, or about 1:1to about 5:1, or about 3:1 to about 10:1).

Clause 29: The method of Clause 1, wherein a weight ratio of thedispersing fluid to the thermoplastic polyester is about 1:5 to about2:1.

Clause 29.5: The solidified particles produced by the method of Clause1.

Clause 30. A composition comprising: particles comprising athermoplastic polyester, wherein the particles have a sintering windowthat is within 5° C. of a sintering window of the thermoplasticpolyester.

Clause 31. The composition of Clause 30, wherein the particles furthercomprise an emulsion stabilizer associated with an outer surface of theparticles.

Clause 32. The composition of Clause 31, wherein the emulsion stabilizercomprises nanoparticles and at least some of the nanoparticles areembedded in the outer surface of the particles.

Clause 33. The composition of Clause 31, wherein at least some of theparticles have a void comprising the emulsion stabilizer at avoid/thermoplastic polymer interface.

Clause 34. The composition of Clause 31, wherein the emulsion stabilizerforms a coating that covers at least 50% of the surface of theparticles.

Clause 35. The composition of Clause 30, wherein the thermoplasticpolyester is present at 90 wt % to 99.5 wt % of the particles.

Clause 36. The composition of Clause 30, wherein the solidifiedparticles have a D10 of about 0.1 μm to about 125 μm, a D50 of about 0.5μm to about 200 μm, and a D90 of about 3 μm to about 300 μm, whereinD10<D50<D90.

Clause 37. The composition of Clause 36, wherein the solidifiedparticles have a diameter span of about 0.4 to about 3.

Clause 38. The composition of Clause 30 or Clause 31 or Clause 32 orClause 33 or Clause 34 or Clause 35, wherein the solidified particleshave a D10 of about 0.5 μm to about 5 μm, a D50 of about 0.5 μm to about10 μm, and a D90 of about 3 μm to about 15 μm, wherein D10<D50<D90.

Clause 39. The composition of Clause 30, wherein the solidifiedparticles have a D10 of about 1 μm to about 50 μm, a D50 of about 25 μmto about 100 μm, and a D90 of about 60 μm to about 300 μm, whereinD10<D50<D90.

Clause 40. The composition of Clause 30, wherein the solidifiedparticles have a D10 of about 5 μm to about 30 μm, a D50 of about 30 μmto about 100 μm, a D90 of about 70 μm to about 120 μm, and a diameterspan of about 0.5 to about 2.5, wherein D10<D50<D90.

Clause 41. The composition of Clause 30, wherein the particles have aHausner ratio of about 1.0 to about 1.5.

Clause 42. The composition of Clause 30, wherein the thermoplasticpolyester comprises one selected from the group consisting of:polybutylene terephthalate (PBT), polyethylene terephthalate (PET),polyethylene naphthalate (PEN), polytrimethylene terephthalate (PTT),polyhexamethylene terephthalate, and any combination thereof.

Clause 43. The composition of Clause 30, wherein particles furthercomprise a thermoplastic polymer selected from the group consisting of:polyamides, polyurethanes, polyethylenes, polypropylenes, polyacetals,polycarbonates, polystyrenes, polyvinyl chlorides,polytetrafluoroethenes, polyesters (e.g., polylactic acid), polyethers,polyether sulfones, polyetherether ketones, polyacrylates,polymethacrylates, polyimides, acrylonitrile butadiene styrene (ABS),polyphenylene sulfides, vinyl polymers, polyarylene ethers, polyarylenesulfides, polysulfones, polyether ketones, polyamide-imides,polyetherimides, polyetheresters, copolymers comprising a polyetherblock and a polyamide block (PEBA or polyether block amide), grafted orungrafted thermoplastic polyolefins, functionalized or nonfunctionalizedethylene/vinyl monomer polymer, functionalized or nonfunctionalizedethylene/alkyl (meth)acrylates, functionalized or nonfunctionalized(meth)acrylic acid polymers, functionalized or nonfunctionalizedethylene/vinyl monomer/alkyl (meth)acrylate terpolymers, ethylene/vinylmonomer/carbonyl terpolymers, ethylene/alkyl (meth)acrylate/carbonylterpolymers, methylmethacrylate-butadiene-styrene (MBS)-type core-shellpolymers, polystyrene-block-polybutadiene-block-poly(methylmethacrylate) (SBM) block terpolymers, chlorinated or chlorosulphonatedpolyethylenes, polyvinylidene fluoride (PVDF), phenolic resins,poly(ethylene/vinyl acetate)s, polybutadienes, polyisoprenes, styrenicblock copolymers, polyacrylonitriles, silicones, and any combinationthereof.

Unless otherwise indicated, all numbers expressing quantities ofingredients, properties such as molecular weight, process conditions,and so forth used in the present specification and associated claims areto be understood as being modified in all instances by the term “about.”Accordingly, unless indicated to the contrary, the numerical parametersset forth in the following specification and attached claims areapproximations that may vary depending upon the desired propertiessought to be obtained by the embodiments of the present invention. Atthe very least, and not as an attempt to limit the application of thedoctrine of equivalents to the scope of the claim, each numericalparameter should at least be construed in light of the number ofreported significant digits and by applying ordinary roundingtechniques.

One or more illustrative embodiments incorporating the inventionembodiments disclosed herein are presented herein. Not all features of aphysical implementation are described or shown in this application forthe sake of clarity. It is understood that in the development of aphysical embodiment incorporating the embodiments of the presentinvention, numerous implementation-specific decisions must be made toachieve the developer's goals, such as compliance with system-related,business-related, government-related and other constraints, which varyby implementation and from time to time. While a developer's effortsmight be time-consuming, such efforts would be, nevertheless, a routineundertaking for those of ordinary skill in the art and having benefit ofthis disclosure.

While compositions and methods are described herein in terms of“comprising” various components or steps, the compositions and methodscan also “consist essentially of” or “consist of” the various componentsand steps.

To facilitate a better understanding of the embodiments of the presentinvention, the following examples of preferred or representativeembodiments are given. In no way should the following examples be readto limit, or to define, the scope of the invention.

EXAMPLES

Example 1. A 100 mL glass kettle reactor equipped with overhead stirrer,impeller, heating mantle, condenser, nitrogen inlet and outlet, andelectronic thermometer was charged with 14.97 g PDMS oil with theviscosity of 10,000 cSt (from Clearco Inc.) and 5.15 g tetraethyleneglycol dimethyl ether (TGD) (from Sigma Aldrich). The mixture was heatedup to between 250° C. and 255° C. while stirring at 350 rpm under slowN₂ stream. Then, 10.02 polybutylene terephthalate (PBT) pellets (meltviscosity 6,000 p, from Scientific Polymer Inc.) was added slowly(around 10 min) while keeping the reactor temperature between 250° C. to255° C. and stirring at 350 rpm. The weight ratio of components was3:2:1 for PDMS oil, PBT, and TGD, respectively. The mixture was stirredat 600 rpm at 250° C. for 1 hour then discharged in dry ice whilekeeping hot paste away from oxygen to avoid autoignition of TGD. Afterdry ice sublimation, silicone oil was removed via washing with hexanefollowed by centrifuging, where the washing/centrifuging cycle wasperformed three times. PBT spherical particles obtained with the averagesize of 30-40 μm. FIG. 3A is an optical micrograph of the particles ofExample 1.

Example 2. A 500 mL glass kettle reactor equipped with overhead stirrer,impeller, heating mantle, condenser, nitrogen inlet and outlet, andelectronic thermometer was charged with 150.0 g PDMS oil with theviscosity of 10,000 cSt and 50.0 g TGD and heated up to between 250° C.and 255° C. while stirring at 350 rpm under slow N2 stream. Then 100.0PBT pellets (melt viscosity 6,000 p) was added slowly (in around 10 min)while keeping the reactor temperature between 250° C. and 255° C. andstirring at 350 rpm. The ratio of components was 3:2:1 for PDMS oil,PBT, and TGD, respectively. The mixture was stirred at 600 rpm at 250°C. for 1 hour then discharged in dry ice while keeping hot paste awayfrom oxygen to avoid autoignition of TGD. After dry ice sublimation,silicone oil was removed via three times washing/filtration by hexane.PBT spherical particles obtained with the average size of 100-150 μm.FIG. 3B is an optical micrograph of the particles of Example 2.

Example 3. A 100 mL glass kettle reactor equipped with overhead stirrer,impeller, heating mantle, condenser, nitrogen inlet and outlet andelectronic thermometer was charged with 15.05 g PDMS oil with theviscosity of 10,000 cSt and 5.30 g TGD and heated up to between 250° C.and 255° C. while stirring at 300 rpm under slow N₂ stream. Then 10.02PBT pellets (melt viscosity 6,000 p) was added slowly (in around 10 min)while keeping the reactor temperature between 250° C. and 255° C. andstirring at 300 rpm. The ratio of components was 3:2:1 for PDMS oil,PBT, and TGD, respectively. The mixture was stirred at 400 rpm at 250°C. for 1 hour. Then 0.05 g (0.5% w of PBT content) AEROSIL™ R812S silicaadditive (from Evonik) was added and stirred at 500 rpm at 250° C. for15 minutes. Final product was cooled down to 200° C. and discharged indry ice. At this temperature, discharging can be done safely. After dryice sublimation, silicone oil was removed via washing with hexanefollowed by centrifuging, where the washing/centrifuging cycle wasperformed three times. PBT spherical particles obtained with the averagesize of 30-40 μm. Sintering window [(Tm-Tc)onset] was 26° C. and (Tm-Tc)was 38.4° C. FIG. 3C is an optical micrograph of the particles ofExample 3. FIG. 4A is a scanning electron micrograph of the particles ofExample 3. FIG. 5A is a differential scanning calorimetry thermograph ofparticles of Example 3 illustrating that their sintering window is notdrastically unchanged from the PBT starting material, which isillustrated in FIG. 5C.

Example 4. A 500 mL glass kettle reactor equipped with overhead stirrer,impeller, heating mantle, condenser, nitrogen inlet and outlet andelectronic thermometer was charged with 75.38 g PDMS oil with theviscosity of 10,000 cSt and 25.58 g TGD and heated up to between 250° C.and 255° C. while stirring at 300 rpm under slow N₂ stream. Then 50.03PBT pellets (melt viscosity 6,000 p) was added slowly (in around 10 min)while keeping the reactor temperature between 250° C. and 255° C. andstirring at 300 rpm. The ratio of components was 3:2:1 for PDMS oil,PBT, and TGD, respectively. The mixture was stirred at 400 rpm at 250°C. for 85 minutes. Then 0.28 g (0.5% w of PBT content) AEROSIL™ R812Ssilica additive was added and stirred at 500 rpm at 250° C. for 30minutes. Final product was cooled down to 200° C. and discharged in dryice. At this temperature, discharging can be done safely. After dry icesublimation, silicone oil was removed via washing with hexane followedcentrifuging, where the washing/centrifuging cycle was performed threetimes. PBT spherical particles obtained with the average size of 30-40μm. Sintering window [(Tm-Tc)onset] was 17.9° C. and (Tm-Tc) was 30.5°C. FIG. 3D is an optical micrograph of the particles of Example 4. FIG.4B is a scanning electron micrograph of the particles of Example 4. FIG.5B is a differential scanning calorimetry thermograph of particles ofExample 4 illustrating that their sintering window is not drasticallyunchanged from the PBT starting material, which is illustrated in FIG.5C. FIG. 6A is a plot of the particle size distribution for Example 4including the size statistics.

Example 5. A 500 mL glass kettle reactor equipped with overhead stirrer,impeller, heating mantle, condenser, nitrogen inlet and outlet andelectronic thermometer was charged with 75.55 g PDMS oil with theviscosity of 10,000 cSt and 25.42 g TGD and heated up to between 250° C.and 255° C. while stirring at 350 rpm under slow N₂ stream. Then 50.07PBT pellets (melt viscosity 6,000 p) was added slowly (in around 10 min)while keeping the reactor temperature between 250° C. and 255° C. andstirring at 350 rpm. The ratio of components was 3:2:1 for PDMS oil,PBT, and TGD, respectively. The mixture was stirred at 500 rpm at 250°C. for 85 minutes. Then 0.28 g (0.5% w of PBT content) AEROSIL™ RX50silica additive (from Evonik) was added and stirred at 500 rpm at 250°C. for 30 minutes. Final product was cooled down to 200° C. anddischarged in dry ice. At this temperature, discharging can be donesafely. After dry ice sublimation, silicone oil was removed via washingwith hexane followed by centrifuging, where the washing/centrifugingcycle was performed three times. PBT spherical particles obtained withthe average size of 30-40 μm. FIG. 3E is an optical micrograph of theparticles of Example 5.

Example 6. A 500 mL glass kettle reactor equipped with overhead stirrer,impeller, heating mantle, condenser, nitrogen inlet and outlet andelectronic thermometer was charged with 75.06 g PDMS oil with theviscosity of 10,000 cSt and 26.07 g TGD and heated up to between 250° C.and 255° C. while stirring at 350 rpm under slow N₂ stream. Then 50.04PBT pellets (melt viscosity 8,500 p) was added slowly (in around 10 min)while keeping the reactor temperature between 250° C. and 255° C. andstirring at 350 rpm. The ratio of components was 3:2:1 for PDMS oil,PBT, and TGD, respectively. The mixture was stirred at 500 rpm at 250°C. for 85 minutes. Then 0.28 g (0.5% w of PBT content) AEROSIL™ R812Ssilica additive was added and stirred at 500 rpm at 250° C. for 30minutes. Final product was cooled down to 200° C. and discharged in dryice. At this temperature, discharging can be done safely. After dry icesublimation, silicone oil was removed via washing with hexane followedby centrifuging, where the washing/centrifuging cycle was performedthree times. PBT spherical particles obtained with the average size of80 μm. FIG. 3F is an optical micrograph of the particles of Example 6.

Example 7. A 500 mL glass kettle reactor equipped with overhead stirrer,impeller, heating mantle, condenser, nitrogen inlet and outlet andelectronic thermometer was charged with 75.35 g PDMS oil with theviscosity of 10,000 cSt and 25.94 g TGD and heated up to between 250° C.and 255° C. while stirring at 350 rpm under slow N₂ stream. Then 50.09PBT pellets (melt viscosity 8,500 p) was added slowly (in around 10 min)while keeping the reactor temperature between 250° C. and 255° C. andstirring at 350 rpm. The ratio of components was 3:2:1 for PDMS oil,PBT, and TGD, respectively. The mixture was stirred at 500 rpm at 250°C. for 85 minutes. Then 0.28 g (0.5% w of PBT content) AEROSIL™ RX50silica additive was added and stirred at 500 rpm at 250° C. for 30minutes. Final product was cooled down to 200° C. and discharged in dryice. At this temperature, discharging can be done safely. After dry icesublimation, silicone oil was removed via washing with hexane followedby centrifuging, where the washing/centrifuging cycle was performedthree times. PBT spherical particles obtained with the average size of80 μm. FIG. 3G is an optical micrograph of the particles of Example 7.

Example 8. A 500 mL glass kettle reactor equipped with overhead stirrer,impeller, heating mantle, condenser, nitrogen inlet and outlet andelectronic thermometer was charged with 82.55 g PDMS oil with theviscosity of 10,000 cSt (from Clearco Inc.) and 28.09 g tetraethyleneglycol dimethyl ether (TGD) (from Sigma Aldrich) and heated up tobetween 250° C. and 255° C. while stirring at 350 rpm under slow N₂stream. Then a blend of 49.50 PBT pellets (melt viscosity 8,500 p, fromScientific Polymer Inc.) and 5.50 g nylon 6 pellets (from sigma Aldrich)was added slowly (in around 10 min) while keeping the reactortemperature between 250° C. and 255° C. and stirring at 350 rpm (theratio of PBT/nylon 6 was 9:1). The ratio of components was 3:2:1 forPDMS oil, polymers, and TGD, respectively. The mixture was stirred at500 rpm at 250° C. for 85 minutes. Then 0.28 g (0.5% w of PBT content)AEROSIL™ RX50 silica additive was added and stirred at 500 rpm at 250°C. for 30 minutes. Final product was cooled down to 200° C. anddischarged in dry ice. At this temperature condition, discharging can bedone safely. After dry ice sublimation, silicone oil was removed viawashing with hexane followed by centrifuging, where thewashing/centrifuging cycle was performed three times. PBT sphericalparticles obtained with the average size of 120 μm. FIG. 3H is anoptical micrograph of the particles of Example 8. FIG. 6B is a plot ofthe particle size distribution for Example 8 including the sizestatistics.

Example 9. A 500 mL glass kettle reactor equipped with overhead stirrer,P4 impeller, heating mantle, nitrogen inlet/outlet and electronicthermometer. The reactor charged with 75.5 g PDMS oil with the viscosityof 30K cSt (from Clearco Inc.) and 49.50 g PBT pellets (melt viscosity6000 p; Scientificpolymer Inc.) and heated up to 250° C. to 255° C.while stirring at 150 rpm under slow N₂ stream for 45 min. Then 0.28 g(0.56% w of PBT content) AEROSIL™ R812S silica additive charged andstirred at 500 rpm/250° C. for 10 minutes. Final product discharged hotin dry ice and washed after dry ice sublimation three times usinghexane. Obtained PBT spherical particles dried 50° C. in an electricoven overnight and particle size measured to be 110 μm (D50).

Selective laser sintering (SLS) was performed using a Snow White SLSprinter system (Sharebot). The thermoplastic polyurethane particulatesof Example 9-3 were deposited using the SLS printer system in a 30 mm×30mm square and then sintered under various laser power conditionsspecified in Table 1 below. Void percentage, Table 1, followingsintering was calculated using the digital microscope software. FIG. 7includes two pictures of the sintered layer at 45% laser power.

TABLE 1 Laser Power (%) Scan Rate Temp. (° C.) % Voids 20 40,000 170 NS25 40,000 170 NS 30 40,000 170 5.1 35 40,000 170 2.7 40 40,000 170 1.845 40,000 170 2.0 NS—not successfully sintered into a single piece.

Example 10. A 500 mL glass kettle reactor equipped with overheadstirrer, P4 impeller, heating mantle, nitrogen inlet/outlet andelectronic thermometer. The reactor charged with 82.74 g PDMS oil withthe viscosity of 5K cSt (from Clearco Inc.) and 0.55 g AEROSIL™ R812Ssilica additive (1.0% w of PBT content) and heated up to 250° C. whilestirring at 300 rpm. Then 55.0 g PBT pellets (melt viscosity 6000 p;Scientificpolymer Inc.) added while the temperature was 240° C. to 250°C. at 300 rpm. When PBT charging completed, rpm increased to 500 rpm andstirred for 60 min. Final product discharged hot in dry ice and washedafter dry ice sublimation three times using hexane. Obtained PBTspherical particles dried 50° C. in an electric oven overnight andparticle size measured to be 86 μm (D50) after screening with sievehaving pore size of 250 μm.

As described in Example 9, the particles of Example 10 were sintered.Sintering conditions and results are presented in Table 2. FIG. 8includes two pictures of the sintered layer at 45% laser power.

TABLE 2 Laser Power (%) Scan Rate Temp. (° C.) % Voids 20 40,000 170 NS25 40,000 170 NS 30 40,000 170 NS 35 40,000 170 7.6 40 40,000 170 5.3 4540,000 170 4.2 50 40,000 170 2.9 55 40,000 170 2.7 NS—not successfullysintered into a single piece.

Example 11. A 500 mL glass kettle reactor equipped with overheadstirrer, P4 impeller, heating mantle, nitrogen inlet/outlet andelectronic thermometer. The reactor charged with 100.23 g PDMS oil withthe viscosity of 18-22K cSt (from Sigma Aldrich), 5.12 g TGD, 50.05 gPBT pellets (MFI: 18 g/10 min from DuPont) and 0.51 g AEROSIL™ R812Ssilica additive (1.0% w of PBT content). Then heated up to 250° C. whilestirring at 300 rpm under slow N₂ stream. Once the temperature reached250° C. (in around 20-25 min), rpm increased to 620. After 75 min, finalproduct discharged hot in dry ice and washed three times using hexane.Obtained PBT spherical particles dried 50° C. in an electric ovenovernight and particle size measured to be 83 and 93 μm (D50),respectively, before and after screening with the sieve having pore sizeof 250 μm. FIG. 9 includes three SEM micrographs (top) of the particlesand three SEM micrographs (bottom) of cross-sections of the particles(samples cross-sectioned using cryo-microtoming).

As described in Example 9, the particles of Example 11 were sintered.Sintering conditions and results are presented in Table 3. FIG. 10includes two pictures of the sintered layer at 45% laser power.

TABLE 3 Laser Power (%) Scan Rate Temp. (° C.) % Voids 20 40,000 170 NS25 40,000 170 7.3 30 40,000 170 5.0 35 40,000 170 2.5 40 40,000 170 2.045 40,000 170 0.7 NS—not successfully sintered into a single piece.

Example 12. A 500 mL glass kettle reactor equipped with overheadstirrer, P4 impeller, heating mantle, nitrogen inlet/outlet andelectronic thermometer. The reactor charged with 100.25 g PDMS oil withthe viscosity of 10K cSt (from Clearco Inc.), 5.14 g TGD, 50.1 g PBTpellets (MFI: 18 g/10 min from DuPont) and 0.50 g AEROSIL™ R812S silicaadditive (1.0% w of PBT content). Then heated up to 250° C. whilestirring at 300 rpm under slow N₂ stream. Once the temperature reached250° C. (in around 20-25 min), rpm increased to 620. After 75 min, finalproduct discharged hot in dry ice and washed three times using hexane.Obtained PBT spherical particles dried 50° C. in an electric ovenovernight and particle size measured to be 83 and 93 μm (D50),respectively, before and after screening with the sieve having pore sizeof 250 μm. FIG. 11 includes three SEM micrographs (top) of the particlesand three SEM micrographs (bottom) of cross-sections of the particles(samples cross-sectioned using cryo-microtoming).

Example 13. A 500 mL glass kettle reactor equipped with overheadstirrer, P4 impeller, heating mantle, nitrogen inlet/outlet andelectronic thermometer. The reactor charged with 100.56 g PDMS oil withthe viscosity of 30K cSt (from Clearco Inc.), 5.16 g TGD, 50.12 g PBTpellets (MFI: 18 g/10 min from DuPont) and 0.50 g AEROSIL™ R812S silicaadditive (1.0% w of PBT content). Then heated up to 250° C. whilestirring at 300 rpm under slow N₂ stream. Once the temperature reached250° C. (in around 20-25 min), rpm increased to 620. After 75 min, finalproduct discharged hot in dry ice and washed three times using hexane.Obtained PBT spherical particles dried 50° C. in an electric ovenovernight and particle size measured to be 123 and 85 μm (D50),respectively, before and after screening with the sieve having pore sizeof 250 μm. FIG. 12 includes three SEM micrographs (top) of the particlesand three SEM micrographs (bottom) of cross-sections of the particles(samples cross-sectioned using cryo-microtoming).

As described in Example 9, the particles of Example 13 were sintered.Sintering conditions and results are presented in Table 4. FIG. 13includes two pictures of the sintered layer at 45% laser power.

TABLE 4 Laser Power (%) Scan Rate Temp. (° C.) % Voids 20 40,000 170 NS25 40,000 170 3.0 30 40,000 170 1.0 35 40,000 170 0.7 40 40,000 170 0.445 40,000 170 0.3 NS—not successfully sintered into a single piece.

Example 14. A 2 L Buchi reactor equipped with anchor and 0.5 D/T P4impeller, heating bath, nitrogen inlet/outlet charged with 800.5 g PDMSoil with the viscosity of 30K cSt (from Clearco Inc.), 42.3 g TGD, 400.6g PBT pellets (Crastin™ S600F20 NC010; MFI: 18 g/10 min from DuPont) and4.1 g AEROSIL™ R812S silica additive (1.0% w of PBT content). Thereactor was purged with nitrogen, sealed, and heated up to 245° C. whilestirring at 300 rpm. Once the temperature reached 240° C. (in around 90min), rpm increased to 650. After 75 min, reactor was cooled down to 75°C. and 400 g heptane was added to help product discharging. Finalproduct was washed three times using heptane and dried at 50° C. in anelectric oven overnight. Particle size measured to be 66 μm (D50) withthe span of 2.01.

Example 15. The same procedure was followed using different a grade ofPBT, which was the same PBT grade used in Example 16 (ResMart Ultra PBT23). The results were comparable by means of particles size anddistribution, 55 μm (D50) with the span of 2.43. Sintering window[(Tm−Tc)onset] was 21.5° C. and (Tm−Tc) was 30.3° C.

Example 16. PBT polymer particles were produced from ResMart Ultra PBT23 in a 27 mm twin-screw extruder (Leistritz ZSE 27 HP). The carrierfluid was PDMS oil with 30,000 cSt viscosity at room temperature. Theconcentrations of components in the final mixture in the extruder areprovided in Table 5. The polymer pellets were added to the extruder andbrought to temperature per Table 5. Then, preheated carrier fluid havingAEROSIL™ R812S silica nanoparticles dispersed therein was added to themolten polymer in the extruder. The screw speed was 1000 rpm. Then, themixture was discharged into a container and allowed to cool to roomtemperature over several hours. The light scattering particle size datais also provided in Table 5.

TABLE 5 Target Actual Poly. Poly. Target Actual Sample Temp. (° C.) LoadLoad Silica Conc. Silica Conc. D10 (μm) D50 (μm) D90 (μm) Span 16A 27050% 41% 1.00% 1.40%  18.8  30.1  47.3 0.95 16B 290 50% 42% 1.00% 1.35% 13.1  19.2  27.6 0.76 16C 290 40% 45% 1.00% 0.81%  14.5  20.4  28.60.70 16D 290 50% 44% 0.50% 0.63%  17.6  25.8  37.2 0.76 16E 270 50% 44%0.50% 0.64%  31.2  45.2  65.2 0.75 16F 290 40% 48% 0.50% 0.36%  41.0 57.1  79.4 0.67 16G 250 40% 48% 0.50% 0.36% 118.0 184.0 286.0 0.91

Example 17. A 500 mL glass kettle reactor equipped with overheadstirrer, P4 impeller, heating mantle, condenser, nitrogen inlet andoutlet, and electronic thermometer was charges with 150.0 g PDMS oilwith the viscosity of 10,000 cSt and 50.0 g TGD and heated up to 250° C.to 255° C. while stirring at 350 rpm under slow N₂ stream. Then 100.0PBT pellets (melt viscosity 6,000p) was added slowly (in around 10 min)while keeping the reactor temperature between 250° C. to 255° C. andstirring at 350 rpm. The ratio of components was 3:2:1 for PDMS oil, PBTand TGD, respectively. The mixture was stirred at 600 rpm at 250° C. for1 hour then discharged in dry ice while keeping hot paste away fromoxygen to avoid autoignition of TGD. After dry ice sublimation, siliconoil was removed via three times washing/filtration by hexane. PBTspherical particles obtained with the average size of 100-150 μm. FIG.14 includes SEM micrographs at various magnifications of the particlesproduced. FIG. 15 is a histogram of the particle size.

Example 18. A 100 mL glass kettle reactor equipped with overheadstirrer, P4 impeller, heating mantle, nitrogen inlet/outlet andelectronic thermometer. The reactor charged with 10.85 g PDMS oil withthe viscosity of 10K cSt (from Clearco Inc.), 10.92 g TGD (from SigmaAldrich) and 10.85 g PBT pellets (melt viscosity 6000 p;Scientificpolymer Inc.) and heated up to 250° C. to 255° C. whilestirring at 350 rpm under slow N2 stream for 25 min. Final product washot discharged in dry ice and washed three times using hexane after dryice sublimation. Obtained PBT spherical particles dried 50° C. in anelectric oven overnight and average particle size measured to be 30-40μm. FIG. 16 includes SEM micrographs at various magnifications of theparticles produced. FIG. 17 is a histogram of the particle size.

Example 19. A 100 mL glass kettle reactor equipped with overheadstirrer, impeller, heating mantle, condenser, nitrogen inlet and outletand electronic thermometer was charged with 11.0 g PDMS oil with theviscosity of 18,000-22,000 cSt (from Sigma Aldrich), 0.05 g (0.6% w ofPBT content) AEROSIL™ R812S silica additive and 5.5 g TGD. Then heatedup to 250° C. to 255° C. while stirring at 300 rpm under slow N₂ stream.Then 8.27 g PBT pellets (melt viscosity 6,000 p) was added slowly whilekeeping the reactor temperature between 250° C. and 255° C. and stirringat 300 rpm. The mixture was stirred at 400 rpm at 250° C. for 60minutes. The final product was hot discharged in dry ice. After dry icesublimation, silicone oil was removed via washing with hexane followedby centrifuging, where the washing/centrifuging cycle was repeated forthree times. PBT spherical particles obtained with the average size of2.5 μm. FIG. 18 includes optical micrographs at various magnificationsof the particles produced. FIG. 19 is a histogram of the particle size.

The above examples illustrate that PBT polymer particles can be producedby melt emulsification methods.

Therefore, the present invention is well adapted to attain the ends andadvantages mentioned as well as those that are inherent therein. Theparticular embodiments disclosed above are illustrative only, as thepresent invention may be modified and practiced in different butequivalent manners apparent to those skilled in the art having thebenefit of the teachings herein. Furthermore, no limitations areintended to the details of construction or design herein shown, otherthan as described in the claims below. It is therefore evident that theparticular illustrative embodiments disclosed above may be altered,combined, or modified and all such variations are considered within thescope and spirit of the present invention. The invention illustrativelydisclosed herein suitably may be practiced in the absence of any elementthat is not specifically disclosed herein and/or any optional elementdisclosed herein. While compositions and methods are described in termsof“comprising,” “containing,” or “including” various components orsteps, the compositions and methods can also “consist essentially of” or“consist of” the various components and steps. All numbers and rangesdisclosed above may vary by some amount. Whenever a numerical range witha lower limit and an upper limit is disclosed, any number and anyincluded range falling within the range is specifically disclosed. Inparticular, every range of values (of the form, “from about a to aboutb,” or, equivalently, “from approximately a to b,” or, equivalently,“from approximately a-b”) disclosed herein is to be understood to setforth every number and range encompassed within the broader range ofvalues. Also, the terms in the claims have their plain, ordinary meaningunless otherwise explicitly and clearly defined by the patentee.Moreover, the indefinite articles “a” or “an,” as used in the claims,are defined herein to mean one or more than one of the element that itintroduces.

What is claimed is the following:
 1. A composition comprising: particles comprising a thermoplastic polyester; wherein the particles have a sintering window that is within 5° C. of a sintering window of the thermoplastic polyester, a D50 up to about 200 μm, a circularity of about 0.7 or greater, and a diameter span up to about
 3. 2. The composition of claim 1, wherein the particles further comprise an emulsion stabilizer associated with an outer surface of the particles.
 3. The composition of claim 2, wherein the emulsion stabilizer comprises nanoparticles.
 4. The composition of claim 3, wherein the nanoparticles comprise oxide nanoparticles.
 5. The composition of claim 3, wherein the nanoparticles comprise silica nanoparticles.
 6. The composition of claim 3, wherein the particles comprise about 0.01 wt % to about 10 wt % emulsion stabilizer.
 7. The composition of claim 2, wherein at least some of the particles have a void comprising the emulsion stabilizer at a void/thermoplastic polyester interface.
 8. The composition of claim 2, wherein the emulsion stabilizer forms a coating that covers at least 50% of the outer surface of the particles.
 9. The composition of claim 1, wherein the particles comprise about 90 wt % to about 99.5 wt % thermoplastic polyester.
 10. The composition of claim 1, wherein the particles have a D10 of about 0.1 μm to about 125 μm, a D50 of about 0.5 μm to about 200 μm, and a D90 of about 3 μm to about 300 μm, wherein D10<D50<D90.
 11. The composition of claim 10, wherein the particles have a diameter span of about 0.4 to about
 3. 12. The composition of claim 1, wherein the particles have a D10 of about 0.5 μm to about 5 μm, a D50 of about 0.5 μm to about 10 μm, and a D90 of about 3 μm to about 15 μm, wherein D10<D50<D90.
 13. The composition of claim 1, wherein the particles have a D10 of about 1 μm to about 50 μm, a D50 of about 25 μm to about 100 μm, and a D90 of about 60 μm to about 300 μm, wherein D10<D50<D90.
 14. The composition of claim 1, wherein the particles have a D10 of about 5 μm to about 30 μm, a D50 of about 30 μm to about 100 μm, a D90 of about 70 μm to about 120 μm, and a diameter span of about 0.5 to about 2.5, wherein D10<D50<D90.
 15. The composition of claim 1, wherein the particles have a Hausner ratio of about 1.0 to about 1.5.
 16. The composition of claim 1, wherein the thermoplastic polyester comprises at least one member selected from the group consisting of polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polytrimethylene terephthalate (PTT), polyhexamethylene terephthalate, and any combination thereof.
 17. The composition of claim 1, wherein particles further comprise a thermoplastic polymer selected from the group consisting of polyamides, polyurethanes, polyethylenes, polypropylenes, polyacetals, polycarbonates, polystyrenes, polyvinyl chlorides, polytetrafluoroethenes, polylactic acid, polyethers, polyether sulfones, polyetherether ketones, polyacrylates, polymethacrylates, polyimides, acrylonitrile butadiene styrene (ABS), polyphenylene sulfides, vinyl polymers, polyarylene ethers, polyarylene sulfides, polysulfones, polyether ketones, polyamide-imides, polyetherimides, polyetheresters, copolymers comprising a polyether block and a polyamide block, grafted or ungrafted thermoplastic polyolefins, functionalized or nonfunctionalized ethylene/vinyl monomer polymers, functionalized or nonfunctionalized ethylene/alkyl (meth)acrylates, functionalized or nonfunctionalized (meth)acrylic acid polymers, functionalized or nonfunctionalized ethylene/vinyl monomer/alkyl (meth)acrylate terpolymers, ethylene/vinyl monomer/carbonyl terpolymers, ethylene/alkyl (meth)acrylate/carbonyl terpolymers, methyl methacrylate-butadiene-styrene (MBS)-type core-shell polymers, polystyrene-block-polybutadiene-block-poly(methyl methacrylate) (SBM) block terpolymers, chlorinated or chlorosulphonated polyethylenes, polyvinylidene fluoride (PVDF), phenolic resins, poly(ethylene/vinyl acetate)s, polybutadienes, polyisoprenes, styrenic block copolymers, polyacrylonitriles, silicones, and any combination thereof.
 18. The composition of claim 1, wherein the particles have a circularity of about 0.93 to about 0.99. 